Subtitled, a good majority of American voice actors for dubs don't fit the character as well as their Japanese counterparts. So I'm perfectly find with having to deal with a language that I can't understand just because I can understand the emotion easier.
Subbed, i actually love the japanese language, and i find that the expressions and everything fits better, seeing how they for most of the times are portraits of japanese characters and sound totally off in english or any other language.
I prefer subbed, but in English. Let me explain, haha. They would show anime here dubbed in French. I don't like the sound of it. And I do watch a lot of other foreign language movies, not just anime, and my rule is to see the ones showing it in VOST (original version, subtitled). For anime though, I usually buy the DVDs and the regular priced ones would have an option for FR/ENG subs. I prefer reading English. However, these dvds can be pricey especially when buying boxsets. So sometimes I'd get those discounted ones but have no other version but french dubbed.
Subs win for me. I also feel the same about foreign films, dubs just feel so artificial. However I find it easier to watch dubbed anime than dubbed films (probabaly because I saw so much kiddy Americanised Anime during my childhood). When it comes to anime dubs aren't a deal breaker, sometimes the english language voice actors do a really good job. I always prefer authenticity though.
Dubbed. I love Japanese, it's a beautiful, beautiful language, but I can't stand having to read off the screen the entire duration of an episode. I'd rather be able to do something on the side (like eat or do homework [not that I like doing homework]) and still be able to hear what's going on.
Also (as we all know [obviously]) English and Japanese don't use the same tones in their voice when they speak, so when I hear japanese while reading english, I can never attach the right emotions to what's being said unless It's obvious.