Since I've only hit the ground twice in my years of riding I'd have to say it was the one where the car rear ended me. Lowish speed, my rear wheel gave it's live to save me. That was the only damage to the bike and I had a mild skined knee.
The other wa on a ride where we cut through a gas station, hit the driveway at a bad abgle and that little 1 - 1 1/2 inch lip was like someone kicked the wheel out. An owie on my thumb.
I've has a few close calls. Hitting a patch of what I thought was old asphault only to find it was gravel at speed. Luckily it was only about 15 feet and straight. That could have been nasty as it was the access road to Fire camp 7 and there was a nasty fire going on at the time. I was alone and might not have been found for days. I've hit a pothole on a decent hard enough to untrue both wheels and actually cause the handlebars to rotate a couple in inches.
But the worst was on Sepulveda pass decending into the San Fernando valley. There ahd been road work and there were big, like 8' by 20' patches that had been repaved, badly. They looked nice bit one had a 1-2 inch lip. I hit that at a bad angle and almost went down, I was all over the road and was just sort of regaining control when I hit the second one. It was flush! If it had not been I was down for sure. About 45 minutes later a ride from the LA Wheelmen came through. One of the ladies on that ride was not as lucky, she went down, ruptured spleen and broken collarbone.