Too many to list............
Saw Social D at a backyard party in OC when I was in high school. Spent a few years in the '80's-90's as a CSUC student hanging out at a venue called The Burro Room, where I caught acts such as Primus, Screaming Trees, Fugazi, The Reverend Horton Heat, Flaming Lips, etc.
I also had the chance to see Nirvana when they had two guitarists (the second being Jason Everman) on the Bleach tour. They were opening up for TAD at the time.
Gogar, I'm not sure if you were there at the time, but I was fortunate enough to see Big Head Todd and the Monsters at the same club I saw Nirvana. You guys had to open for a really crappy local band called NorthRoxx
and even had to set up in front of their equipment. You guys blew me away, one of the best shows I've seen.
I've also had the opportunity to open for Cake and No Doubt, but that's a different story for another day.