Having lived and studied there I may be slightly biased, but I think San Diego really gives you the best of both worlds.
The beautiful beaches are exactly what you imagine when you think of southern California, but I also love the big city bustle of the Downtown Gas Lamp Quarter. Not to mention the city's proximity to Mexico - in 15 minutes you can drive (or walk if you wish) across the border.
Often the menus on board your cruise reflect the port you’re docked in, so don’t be afraid to try something different and ask the crew for tips, they’re trained experts in their area so they know what they’re talking about.
If you're feeling particularly adventurous then why not try the local delicacies when you're in port, and really immerse yourself in the destination!