I'm leaving my S&G boat "au natural" however, it seems that many folks like the brighter colors for the bottom/sides for SAFETY reasons. If you're out on a lake with boat traffic, a light color is going to be much more visible than something that is darker and blends in with the water or bank.

As for paint, I've heard good things about Interlux Interthane Plus (two part). It's available from most marine distributors (such as West Marine) and is formulated to go over most epoxies. (I've also heard that an opaque color highlights hull flaws much more than varnish, so make certain that everything's faired out nicely before you paint. :-) )