Personally I prefer to watch every movie/series/anime in their original language because I believe it's the best to express it. So I always get the subs to watch anime. BUT there are some situations where a certain anime is broadcasted by your country's TV stations in dubbed version. If you start watching the anime in a dubbed version you will eventually get used to the characters' voices, even if their original Japanese are "better". Besides hearing the characters talk in your mother language can always win your heart. In conclusion I believe it depends on what are get used to watch.

P.S. I am wondering why everyone is posting with the same name e.g. "Random Anime Otaku" Of course my name is not original either but it's really confusing reading a forum like this. O.O