rh, What do you like to do? I live one hour away from Santa Barbara, in fact my daughter went to UCSB. There no doubt that it is a nice place, but I don't know if it would be worth your time. Traffic is getting pretty bad around there. My daughter has said that it is more of a two hour drive, and has taken her three hours.
SB is one hour to the north. One hour south of me is Los Angeles. LA has Six Flags Magic Mountain, Disneyland, Knotts Berry Farm, and lots other things, including traffic. LA to SD is about two to three hours south. Last year we took our vacation in San Diego. We rented a condo on the beach, although that might be getting a little late for you to do that. We rented a boat two of the days and went in the bays. One day I took my son to Legoland in Carlsbad.
Remember CA is a great place to live and visit, but it is certainly in no way a scenic place. I don't think that SB would be worth your time. It will take at least 2 days out of your trip. A good trip would be to fly into LA. LAX is a big huge airport. Burbank is great to fly into and out of because it is small. Although I don't know how it is to rent a car. You could spend a couple days in LA and then go down to San Diego.
There is also Universal Studios. They have the new Harry Potter land there. They also have the City walk which is a bunch of shops outside of Universal Studios.
If you give us a little more of what you like to do we can narrow it down for you.