UCSD is in a beautiful area. I would have loved to go to UCSD, unfortunately my grades weren't that high during high school. Only thing is I keep on hearing that UCSD has no social life. I'm not so sure how true that is, but UCSD is more of a science/math school, if that makes any sense. CSUN? I applied there also, beautiful campus too. I have no idea how good their Comp. Science department is. Anyway, back to your question. It seems like CSUN is the cheaper option, you'll be living at home since your a local, so you won't get the whole "college dorm" experience. Is that something you would want? If so I'd say go to UCSD. San Diego is only 3 hours away, so you could go home pretty much anytime you want (mostly weekends I'm assuming).