Bill posted a great link to a discussion we had about this topic some time ago so make sure you check that out.
My best color this spring has been a kelly green body (dark green) on a two tone light over dark green head. Solid black has been good some days and purples are always a safe bet. One color that I did not see mentioned in the post Bill linked to that can be hot in the spring is light blue / powder blue on a black head.
Lots of guys have their faves… hopefully some more guys will be willing to share theirs here.