People argue about a lot of things. One thing I've seen a considerable amount of arguing about is as to whether subtitled is better than dubbed or vice versa. While the amount of debate has gone down considerably since DVDs generally contain both versions now it is still debated frequently on anime forums, chat rooms, boards, etc. It is not limited to anime; this debate extends to basically any foreign film. If you were to look for them you'll likely find dozens of very well done posts on this on many websites/blogs/forums. Some examples are these articles: anime news network, USA Anime.
In general I prefer subtitled over dubbed. This is not always the case since there are some dubs that are of excellent, and in some cases, even better quality. This is not limited to anime or even Japanese films. When I watch a Russian, Hong Kong, or Swedish film, I prefer to watch it subtitled. I often feel that a lot is lost in translation (and for live action the mouth movements not matching the voices can become very annoying). Some sub titles are pretty bad though particularly those done in Hong Kong.
Some examples in which I consider the dubbed version to be better or prefer to watch it dubbed:
-Lupin III TV series and movies generally since a lot of the references were for things in the seventies that make no sense to me and the dub is more current. I also like the voices more than the Japanese ones.
-My Neighbor Totoro. In this case I do not think the dub is superior to the original language I just prefer to watch it without the subtitles. This is true of a lot of the Ghibi films.
Some examples in which I consider the subtitled version to be better and do not watch it dubbed ever:
-Love Hina. I found the voice acting in the English version to be very aggravating.
-Ranma ½. I prefer the original Japanese voices.
-Detective Conan/Case Closed. I just do not like the dubbed version (the changing of the characters names really annoy me for some reason and the cases require an understanding of Japanese culture that doesn't translate well).