Santa Cruz is a special place. It's a college town and it is right near the Bay Area, but it is still a bit isolated by the high redwood covered mountains of the San Francisco Peninsula behind it. Really, the diving there is definitely a challenge and is generally only mediocre, but everything else about the town is fantastic. It has some of the best surfing in California at Steamer Lane off of Lighthouse Point. It's a wonderful place for biking along the shore or hiking in the redwoods. It's a place for walking on the beach and then enjoying a dinner on the wharf. Later stop at the Catalyst for music. Up the coast a bit is Ano Neuvo island with its thriving Elephant Seal colonies where you can take guided tours of this incredibly natural place. There is a lot of area for diving, but you have to be very hardy for it. Just driving north up Hiway 1 from Santa Cruz will take you past some of the most scenic coastline in the world. Nearby is the Bay Area and very good diving of Monterey. There is so much to do in Santa Cruz.
Cowells Beach and The Wharf. It's great for learning to surf.
For the big waves that Santa Cruz is famous for, check out When You Can't Dive...
For more about diving the Santa Cruz Area