Monterey Bay Aquarium is world famous and pretty amazing if you have a day/afternoon off to check it out. nice beaches in the area of monterey/carmel & santa cruz/capitola/aptos and everything in between, but weather (especially as autumn sets in) is sporadically beautiful/overcast. some cool 'metal' bars in SF like Pop's and Zeitgeist. Zeitgeist may give you a decent idea about how 'yuppie' and 'dirtbag' converge in the Norcal sensibility (PBR and craft brew side by side). if you're into beer check out Toronado Pub in SF.
i think you're a few days early for a handful of pretty cool tours hitting the area, but you should do some searching, there are always metal shows happening in the sf bay area