That.I take the Zac Bertschy approach: if it's a show about Japanese people (i.e. Death Note, Paranoia Agent) I will watch it in Japanese. If it's a show about the West, space, etc. (Cowboy Bebop, Irresponsible Captain Tylor), I will watch it dubbed.
I could never stand watching the Cowboy Bebop sub for the simple fact that all the characters have Westernized qualities, so the language they were speaking was unfitting. Similarly, Death Note is obviously set in Japan, so them speaking all-English seemed a little off.
Though, if the dub/sub is really, really bad, I will watch the opposite despite the setting.
Also, if access to the anime dub is more convenient, then I'll just go with the dub for sake of time.
For those of you hardcore subbers, I never really got why you think English voice actors don't put as emotion or aren't as realistic as other voice actors, and then you use 4kids as an example. Last time I checked, 4kids didn't make every single dub.
For instance, the Eureka Seven dub, the Cowboy Bebop dub, the Neon Genesis dub, and Hayao Miyazaki movie dubs are all ridiculously well-done. I actually liked the English dub of Castle in the Sky more than the sub because Pazu's voice was irritating in Japanese.