Honestly, the simple answer to this is, whatever I happen to wach it in first. 
     For example, I was shown Fullmetal Alchemist Dubbed, so subbed sounds weired to me now.  However I wach all the Studio Ghibli films subbed, because that's how they where introduced to me. 
     When I'm with friends or showing family I'll do dubed, just so we don't have to pause or rewind every time someone misses something. 
     Also something I like to do is wach it in the native language of the characters, (so Bleach would be Japanese, Fullmetal Alchemist would be English, Attack on Titan would be German, etc...)
but that's not always possible, so I wach whatever is the first I see it in. Which most of the time is Subed. :)

Complex Addition:
    I do find myself waching subbed more.  I guess this is because I just like the way it sounds, lol.
  Well that, and I ushaly find shows easer when there subbed then dubed. 
     The only real down side to subbed is I have to pause it if I'm doing something elts so I can keep up with the story, or I'll try to fallow it, but the subtitles disapear befor I can read them, but other then that it's pritty good. I like them :)