I'm not surprised by the fervor of the Always Subtitle people. Catch a 4Kids One Piece, and you might swear off the English language entirely.
That said, I have to go the exact opposite with everything foreign, not just anime. Always dub, always localize. I actually really don't understand how people can legitimately argue the other way.
As I see it, if I don't speak the language fluently, I'm *always* going to miss out on the little verbal cues and connotations that native speakers take for granted. Japanese voice acting isn't "better" than the even the worst English voice acting, because it's just noise to me. Meaningless sound, chopped up into word-bits.
Because I don't speak the language, it's impossible for me to ever know if a Japanese voice actor is doing a good job--they could be over-acting terribly, for all I know! In other words, when it's subbed, I always miss out on emotional content and verbal shades of meaning.
The other thing (mentioned by several in this thread) is that if I'm looking at the bottom of the screen, I'm not looking at the center. If I'm not looking at the center of the screen, I'm missing action. Simple as that.
I scratch my head whenever I hear someone say something like "dubs are content rape" or "dubs lack emotion." Do you guys not understand that both dubs and subs are... translations? So... both are inevitably going to involve missing/shifted meaning--is READING a translation inherently better than HEARING it? Of course not. In fact, exactly the opposite is true.
I think part of this debate hinges on the similar "translation vs. localization" debate. Should a translator struggle to retain foreign concepts/jokes/puns wherever possible, or should a translator localize those elements into similar, more familiar concepts/jokes/puns for the intended (in this case) English audience? In my opinion, the answer is emphatically the second one. Unless I suddenly become a native speaker, I'm never going to really understand those ideas--so change them! Change them to something I will understand, something I'll immediately identify with and respond to.
Take One Piece and the word "nakama." I watched a fandub a while back, which included a huge, inexplicable text-dump (..err... a lot like this post...) inserted at the beginning of the episode on the meaning of "nakama" and their refusal to change it. No matter how much text they unloaded into my eyeballs, it didn't make the untranslated word any less awkward and distracting. Then I watched the same episodes, this time dubbed by Funimation. Those odd cultural interruptions were gone, replaced by a deeper understanding (thanks to clever, unobtrusive localization). And the voice actors were great, too.