I went for the Khan era gear, though the TNG movie/late DS9 stuff always appealed to me. And still does. Oddly, my custom designs could be seen as a mix of the two.
I've always liked the TNG (s3 onwards) as it fits the feel of the show quite well, but for some reason I've recently wanted to put together a spandex s1 uniform. I really don't know why as I hated it growing up.
The new 2009 uniforms are also the perfect adaption to the classic ones and as for TMP - I hated most of them, but... liked the short sleeve variants.