I made the drive to Huntington Beach this morning and picked up my new (used) bike. I didn't get back until after noon and it's 90-ish outside so, of course, I took it for a spin (because I'm an idiot). Here is me right after its shakedown cruise:
It's a Centurion Diamond Back somethingorother. The bike guy, Mike, estimates that it is from the early 90s, which lines up with what I could find out about it on the net. It is much lighter than the bike I have been using, which is nice and disconcerting at the same time. It is a 14-speed with Shimano 105 shifting and the levers on the downtube, which isn't nearly as nice as those STI setups but it is better than the straight friction shifting that I had been using and for $280, I'm not complaining.
If you're looking for a used, not high-end bike in Southern California, drop Mike a line and see what he has in stock.