This list went through some really drastic changes...

My favorite album without a doubt is Death of a Bachelor; then A Fever You Can't Sweat Out; Too Weird To Live, Too Rare to Die!; Vices and Virtues; Pretty. Odd.; Live in Chicago; and finally; All My Friends, We're Glorious.

15) Behind the Sea - Alternative Version (Live in Chicago)
This almost didn't make the list. I'm really not the biggest fan of Pretty. Odd., and it took me quite a while to warm up to it. Sure, I enjoyed this song, but I wasn't going to call it my favorite. Really what changed it was falling in love with both Northern Downpour and its live recording. Then I heard the live recording of this song, and it just lead to this.
Most powerful line(s): "And we're all too small to talk to God"
Additional: "And men all played along to marching drums and boy, did they have fun behind the sea" "Yeah, we're all too smart to talk to God"

14) House of Memories (Death of a Bachelor)
I was surprised this song got so high on the list. It used to occupy the ninth spot, but I always thought I would've preferred Memories from the Vices and Virtues album over this song. I listen to it a LOT though, and I love the lyrics, so I just had to keep in the list.
Most powerful line(s): "In your house of memories"
Additional: [entire chorus] "I was a fool" "Is this taboo?" "As I remember you"

13) Vegas Lights (Too Weird To Live, Too Rare to Die!)
I don't really have much to say about this song. I just couldn't leave it out. I guess I just really like how much it reminds me of Sesame Street, like with the counting down. Brings me back to my childhood, but at the same time, the lyrics themselves keep me in the present, so it's still super powerful and just really enjoyable in general.
Most powerful line(s): "We're swimming with the sharks until we drown"
Additional: "Do it (5 4 3 2) One more time in the Vegas lights" "Oh woah oh oh (5 4 3 2 1)"

12) Casual Affair (Too Weird To Live, Too Rare to Die!)
I love this song sooooo MUCH. I can't stop listening to it. This song almost didn't even make the playlist in the first place because I initially interpreted it as talking about sex (and it technically still is). Then I later looked up the meaning of a "casual affair" and now it's all good.
Most powerful line(s): "Affair" (last line of first two choruses)
Additional: "A lover on the left, a sinner on the right" "Lay in the atmosphere - a casual affair" "Hey, a casual affair that could go anywhere and only for tonight"

11) LA Devotee (Death of a Bachelor)
I LOVE this song. I noticed as I was making this list, though - I kept pushing it back, and I felt really bad because I knew this was one of my favorites! It almost hit the number 13 spot, but I was able to bring it back up; I couldn't deny just how much I loved it.
Something you should probably know: when I was first getting into Panic!, there were only seven songs in my playlist that I would listen to over and over again. All seven of these songs made it onto the list, just so you know, and LA Devotee was the seventh. Ready to Go was the fifth, by the way.
Most powerful line(s): "The black magic of Mulholland Drive - swimming pools under desert skies, drinking white wine in the blushing light, just another LA devotee" (key change)
Additional: "Static palms melt your vibe, midnight whisperings" 

10) Girls/Girls/Boys (Too Weird to Live, Too Rare to Die!)
This song almost didn't make the list, but it grew on me. A lot. Really fast. I love Brendon Urie's voice on this one. This song really showcases his amazing vocal range, and it's so fun to sing with my friends that also enjoy this band. We blasted it while getting our makeup done for the Arsenic and Old Lace play my sophomore year of high school.
Most powerful line(s): "And love is not a choice"
Additional: "But I don't ever want to be your boyfriend" "Sophisticated, manipulated" "And never did I think that I would be caught in the way you caught me - push another girl aside and just give in"

9) The Ballad of Mona Lisa (Vices and Virtues)
This song almost didn't make the list, but especially after falling in love with the music video, I had to include it.
Most powerful line(s): "There's nothing with wrong with just a taste of what you paid for" (last line)
Additional: [entire chorus] 

8) Far Too Young to Die (Too Weird to Live, Too Rare to Die!)
Not much to say about this one either, it's just a really good song.
Most powerful line(s): "We're far too young to die" (last line)
Additional: "You never could control me" [entire chorus] "Don't let me do this to myself"

7) Emperor's New Clothes (Death of a Bachelor)
What bad thing can I say about this song? It was the third song I heard by them, and the second song in my original playlist (it was also used to be number three). I didn't really pay too much attention to it the first few listened because the title didn't really interest me, but when I finally did, it became an instant favorite. I also loved the story of The Emperor's New Clothes as a kid, so it was a nice reminder since I had completely forgotten about it's existence.
Most powerful line(s): "So close I can taste it"
Additional: "And if you don't know now you know, I'm taking back the crown, I'm all dressed up and naked - I see what's mine and take it" "If it feels good, tastes good, it must be mine" "Finders keepers losers weepers"

6) Let's Kill Tonight (Vices and Virtues)
This is officially the first P!ATD song that I learned on my ocarina. It was also the fourth song in my initial list of P!ATD songs. It actually used to occupy the fourth spot in the list, as well. This is one of my friend's favorite songs, and it quickly became one of mine (even though I was unsure if it was clean or not).
Most powerful line(s): "May your feet serve you well, and the rest be sent to hell"
Additional: "Let's kill tonight, kill tonight - show them all you're not the ordinary type, let's kill tonight" "Stomp your feet and clap your hands"

5) The Only Difference Between Martyrdom and Suicide is Press Coverage (A Fever You Can't Sweat Out)
This song almost made the number one spot (used to be in number two) and it's the song that I currently still play a lot, besides Casual Affair, Victorious, and Emperor's New Clothes. It's probably the one I play the most out of those.
This story is similar to that of Nails for Breakfast, Tacks for Snacks from the same album. I just like this one a LOT more. It also held the sixth spot in my original playlist.
Most powerful line(s): "Swear to shake it up I'll you swear to listen, oh we're still so young, desperate for attention"
Additional: "Sit tight, I'm gonna need you to keep time, c'mon, just snap, snap, snap your fingers for me - good, good, now we're making some progress, come on just tap, tap, tap your toes to the beat" "And I believe this may call for a proper introduction" "Applause, applause - no wait, wait"

4) I Constantly Thank God for Esteban (A Fever You Can't Sweat Out)
This song also almost didn't make the list. I was surprised to find that I liked this one more than the previous song - this one was also the "meh" song for me in the past. But, here we are. I can say it was one of the first songs by Panic! that I learned on my ocarina.
Most powerful line(s): "Strike up the band" (after bridge)
Additional: [entire verse 1] [entire chorus] "And I for one can see no blood from the hearts and the wrists you allegedly slit, and I for one won't stand for this - if this scene were a parish you'd all be condemned" "Da da da da da da da da da da da da da da da da da da da da da"

3) This is Gospel (Too Weird to Live, Too Rare to Die!)
This was one of the first songs I listened to by Panic! (it was the fourth). This song is not only my favorite song by Panic! to play on my ocarina, but it's also one of my favorites to sing. I do listen to a clean version, however.
Most powerful line(s): "If you love me let me go" 
Additional: "'Cause these words are knifes that often leave scars, the fear of falling apart" "Their gnashing teeth and criminal tongues conspire against the odds, but they haven't seen the best of us yet" "Don't try to sleep through the end of the world and bury me alive, 'cause I won't give up without a fight" "Truth be told, I never was yours"

2) Northern Downpour (Pretty. Odd.)
This song is another one of those songs that barely made the list. It used to be at number ten, and before that, I never really payed attention to it at all. I've listened to it so much that it's grown on me, like a lot. I love the speaker talking to the moon in this song, it's just so beautiful, and I love the simplicity of it.
Most powerful line(s): "Hey moon, please forget to fall down - hey moon, don't you fall down" (first chorus)
Additional: "Northern downpour sends its love" "Just like broken glass to me" "I missed your skin when you were east" "I know the world's a broken bone, but your melt your headaches, call it home" "You are at the top of my lust, drawn to the ones who never yawn" (live version)

Honorable Mentions

Ready to Go [Get Me Out of My Mind] (Vices and Virtues)
This song used to occupy the number 12 slot. It was also one of the first songs I heard by them.
The Good, the Bad, and the Dirty (Death of a Bachelor)
This one used to occupy the number 14 slot, but other songs took its place as I got more familiar with the band.
Girl That You Love (Too Weird to Live, Too Rare to Die!)
This one used to occupy the number 13 slot.
Death of a Bachelor (Death of a Bachelor)
This used to be in the number one slot...it was the first song I enjoyed. This is the first time this kind of song has not ended up in the list at all.
Victorious (Death of a Bachelor)
This song used to be in the number 10 (formerly 3) slot, but not only did I really dislike playing it in band and the music video, but Brendon Urie's ego has kind of made this song harder to enjoy. Keep in mind that like Death of a Bachelor, this was the first song I heard by them, so this not showing up in the list is a rarity.

1) Nails for Breakfast, Tacks for Snacks (A Fever You Can't Sweat Out)
From the moment I heard this song, I knew exactly what it was talking about. The reason why I chose the most powerful line is because it is the line that gives me chills due to so accurately bringing me back to a past scenario that happened in my life. Ever since, I had loved the song, and it's been one of my favorites, and I just love the ending so much. I love when songs end quietly with a line from the line (i.e: Trouble and Baby Blue by Cage the Elephant).
This used to be in the number 8 slot because I was still seeing through my nostalgia. I listen to this song too much, and I can't deny how good it is.
Most powerful line(s): "The hospice is a relaxing weekend getaway where you're a cut above all the rest" (last time)
Additional: [entire chorus] "Sick and sad patients on first-name basis with all the top physicians" "Watch your mouth, oh oh oh because your speech is slurred enough that you just might swallow your tongue, I'm sure you want, want to give up the ghost with just a little poison that" [entire bridge] [entire song] 

.

I know what you're thinking. Where's I Write Sins Not Tragedies? Yeah. The lyrics aren't exactly clean. So...sorry (not).

Songs not included:

Don't Threaten Me With a Good Time
Hallelujah
Crazy=Genius
Golden Days
Miss Jackson
Nicotine
Collar Full
Hurricane
Sarah Smiles
Do You Know What I'm Seeing?
London Beckoned Songs About Money Written By Machines
Camisado
Time to Dance
Lying is the Most Fun a Girl Can Have Without Taking Her Clothes Off
But it's Better if You Do
I Write Sins Not Tragedies
There's a Good Reason These Tables are Numbered Honey, You Just Haven't Thought of it Yet
Build God, Then We'll Talk