Berkeley's fine, though 90 minutes or so away. At 40 cents or so a mile, there is some cost involved - money that could be spent at:
The Beat - downtown Sac @ 17th and J
Dimple Records (several locations)
Esoteric (on ElCamino) is sometimes worth a stop, when you're at Tower anyway
There's also a little, but not-bad, shop between the famous nightclub and the equally famous bookstore downtown, right across from the capitol. Seems to be the club is something like the Garage or Capitol Garage. In any event, I think the location is between 12th and 15th on L street.
Finally, there's a shop in North Sac called, I believe The Underground. This location isn't great, but others are better (Chico, Oroville, etc.)
Or consider a stop in nearby Davis, on your way to Berkeley, if you must. Aardvark and others.