Strangely enough, I find that the opposite is true for me. I very seldom listen to trance (I don't have any trance on cds or mp3), but when I'm coding, there's no substitute for it. Might be the repetetiveness, the fast beat or the (usually at least) lack of lyrics, but it sure makes me code faster and better.
There's a very nice shoutcast called Tag's Trance Trip that I recommend if you'd like to try if it works for you too.