How old are you? Is the purpose of the trip primarily riding or just having fun partying, meeting girls, etc? Keep in mind that the legal drinking age is 21.
I'm a Bay Area native but moved up here last year mainly because the trails are way better than the trails around the bay. There are a lot of good trails but they are far apart. My top five would be Skeggs, Soquel demo forest, Auburn trails, Downieville, and Mr. Toad's Wild Ride. Look em up on mtbr.com
Definitely gotta spend some time in San Francisco. Blondie's is good but the best thing about it is that it's in the Mission district which has tons of small restuarants and bars so you can barhop all night. Well, only til 2 am.
Alcohol is dirt cheap compared to BC prices. Explains why I drink so much less up here.
Some of the other places are worth checking out but think about if you really care to end up in a tourist trap (fisherman's wharf, cablecars) or a haven for old people like Carmel. Carmel is beautiful but holy fuck it's boring after sunset. Go to Santa Cruz. Camp out on Manresa beach.