Go for it...

What most people do not know is that some of the first people to wear navel rings were surfer GUYS...not chicks. I have a 14 g. banannabell in mine, and I prefer it over a CBR, however, I have friends who would disagree with me, and say that they prefer a CBR over a bannannabell because it is easier for them to clean, and it flops more to one side rather than "sticking out" ...(which makes no sense to me, because mine is completely comfortable, but whatever)
I think you should get whatever you think you can keep clean, and remember, you are not doomed to a life of liveing with whatever your origional choice is...it is changeable after a period of time, which is why I say pick the one you think you can best keep clean. As for sleeping on it...forget it. It hurts, and you will regret it. Learn to sleep on your side or your back or something.

Just don't go Body Boarding after you had it pierced! This could really damage the piercing. Meaning it probably would rip out. Ouch! At first I thought guys? Belly pierced? Ugly, But then I saw a actual pierced mal Belly button and it is soo sexy!

i think it'd be cool! although i have to say, my fav piercing on a guy is nipples, followed by eyebrow.