I use my regular prescription glasses, with a chumps strap.
My frames are pretty comfy. The bridge of the frame isn't adjustable, it just rests on my nose like sunglasses would. I chose that style for comfort. The lenses are held in by the plastic frame instead of screwed in. So in a way, they're kind of like sport frames but they just don't have a very sporty appearance.
I have some kind of durable (probably polycarbonate) Transitions lenses but I don't think they actually shade my eyes enough for them to even matter (they just kind of hide my eyes from sight). After reading this thread, I think I might see if I can get my lenses coated with the "XTrActive" version of Transitions.
I always used to have problems with the thinner metal rims that hold the lenses in with screws. They just seem to wear out quickly, and the lenses would pop out on me. I haven't had that issue with the plastic rims, which I've been using for about 4 years now. The lenses stay in, and they're very comfortable without that annoying adjustable bridge that most glasses come with.
Yes, I'm a newbie; because of that I've had my fair share of run-ins with rocks in all the playparks. My glasses have held up through all of that. My Dad tagged along with me on my river class (it was his first time too) and he lost a (screw-in) lense during one of his flips on the Platte.