Not from Cali but I'm gonna be in Santa Cruz for a couple days, where is the best place to buy beer? Cheers!
If you are looking for a bottle, try AJ's Chevron, sounds odd but they have a great beer selection, corner of Park Rd and Soquel Drive, BevMO on 41st... If you dont mind being served by an A-hol* you can try 41st ave Liq., but be warned, he would rather read the paper or talk to his beer delivery guy than you. Once was bad, twice, shame on me, third time, I wont go back, ever. If you want a really good beer on tap, brewed locally, you have to go to Sante Adarius in Capitola, check their hours on facebook I think its Thursday - Sunday only.
A second rec for AJ's. 41st Ave. has a good selection as well. New Leaf and Whole Foods are additional options.