Any nice places to river/lake kayak in the SF Bay Area?

I live in Palo Alto, and this summer, I want to try a bit of kayaking for fun. I'm 16, pretty athletic, and up for any challenge (fast rivers sound fun). I would like to go on long, scenic trips with my friends and eventually get into kayak fishing. Are there any nice places around the SF bay/Santa Cruz where I can rent a kayak and experiment with kayaking? I have heard that Loch Lomond and Coyote Creek are nice places, but do they rent out kayaks?

Any input is greatly appreciated.

San Pablo Res and Lake Del Valle both have kayak rentals in the summer. You can rent a kayak right on the bay in Oakland at Calif. Canoe and Kayak. Wear your PFD.
Fast rivers? Try the Sierras.