English or Japanese

[L]

There are some dubs that simply outshine the original cast of voice actors for me.
Burst Angel, Elfen Lied, Chobits for example, while others failed due to some other reason.
DBZ had good voice actors for both ends, but Funimation toned down the serious and turned up the silliness, even the music I think ruined the dubbed for me (Bruce F. just.. There's very few good tracks in his entire portfolio)

While others are just plain horrible.
The voice actors are 'okay' for Naruto, they just don't fit the characters at all.
Naruto can just -never- be taken seriously no matter the situation in the dubbed version, he sounds 5 when in the same scene in the original version the scene could give you goosebumps it was so awesome.

So really, it just depends on how everything 'sounds right' when watching..

 

[Prozac]

Really depends on the first language I watch the show in.

 

[KelesK]

Well, some anime series are better in English rather than Japanese and vice versa. An example is DragonBall Z, in English dub, Goku's voice is alot better than the Japanese one.

I second this, the Japanese Goku is unbearable