Been to LA and San Diego. I love San D. The weather is between 65-80 pretty much year round. Plus TJ is a hop on the Trolley away, if you want to party down cheap & nasty. LA is a shithole on the other hand. I was at the Greyhound Bus Terminal there, and there were litterally SCORES of black gang members selling crack right out in the open. They would approach you and ask if you wanted it.
Las Vegas is also about a 4 hour ride from San D as well. Not to mention, that you could probably get a charter there for about 90 bucks. An added perk. If you make the drive though, and it is summertime, you'd better make DAMN sure that you either 1. Have a good car w/ good A/C, or 2. Make the trip at night, when it isn't 120 degrees. The desert is brutal in the daytime. I found all that out the hard way.