I live down in La Jolla right now and attend UCSD undergrad. I love it, don't need to go on about the advantages/disadvantages over L.A. since you're probably well aware of how much more laid back it is here.
I think Encinitas or Del Mar are probably your best bet, Osides and Carlsbad are a bit far for commuting to UCSD IMHO. If you can swing the cash, La Jolla IMHO is bar none the best place to live down here. Even with 2 roommates, I pay an arm and a leg for the 3-bedroom house we're living in, but I absolutely love it down here. The weather's awesome, there's no smog, the people are so laid back, and the cars...I see all the crazy Mercs down here (SLR, SL65, etc. on a daily basis), plenty of Porsches, Ferraris and the other day I even drove past a Bugatti Veyron just parked on the side of the street.
Night life is pretty good too on the weekends. There's lots of new-rich people down here so the clubs are usually poppin, there's always a drink-special somewhere, it's good times.
I can't say enough about school too, it's awesome. They're expanding and building left and right, in the next few years it's really going to come together. There's always parking on campus, people are so friendly, always ready to help, classes are easy to get and lots of pretty girls
Feel free to PM me if you have any specific questions Brad, it would be fun to see you down here man.