As both a piercer and a wearer, I must say that genital piercings rock! I've got a 2ga apadravya (about 1/4" diameter) and my wife loves it. It's actually more of a 'half'-adravya as my wife puts it since I have the underside of my penis split, so the barbell only goes through the top of the head.
I also have a 00ga guiche which is fun to have tugged when she's going down on me, but lately it's been getting irritated so I've taken it out. The hole never closes so if I want to play with it I can just throw jewelry back in whenever I want.
I've got a few other piercings here or there, but I think my apadravya is my favorite as far as functionality goes. I've had a few other genital piercings but I took most of 'em out because of the split (kinda hard to have a frenum when there's no frenum left).
I've also split my tongue, which is a ton of fun to use in and of itself.
Jason