Depends on what I'm doing if I'm just going out for a ride for the heck of it I usually were jeans and a t-shirt helmat and vest if I'm going far. If I'm working on something I'll were my breaches tall boots and depending on the temp.I might were my sports shirt or a sweater and in the dead of winter I'll ocassionaly were my coveralls. Quite a funny site haha.
For riding I wear a pair of breeches, my middle school gym shirt, gloves, a helmet, and if we are jumping I wear a vest as well. I used to always wear jeans for lessons, but then my instructor insisted that we all wear breeches. Oh yeah, and I also wear my riding boots, can't forget those.
Whatever I have on. If I'm riding for someone, I'll put jeans ans boots and all that on (and yes, I actually own the whole getup, english even, but it's kicking and screaming to get it on me), but usually it's bareback, barefoot, shorts and whatever kind of shirt I'm wearing. Go on, tell me how improper and dangerous that is.