I graduated from SDSU in the 90s and still live in San Diego. I loved it here so much, I decided to stay.
First, SDSU has a good nursing program, as far as I can tell. I have met a few people in that program, and know it's difficult to get into, but I'm no expert on it.
Classes can be very difficult to get into. SDSU is the largest CSU campus and since the budget cuts (which is the environment I had to deal with when I went there), they've had to reduce staff and limit enrollment. Plan on 5 years to go to SDSU and maybe take a few GE classes off-campus. Science classes might be easier to get into since the school is more business-focused.
Campus life is great, but ultimately what you make of it. It has a large campus with lots of activity. They are currently re-building the student center--I'm not sure when it will be complete. Back when I was there, it was known as a big party school, but they've tried to overcome that image in the last few years. I wouldn't call it a commuter school since so many students live either in the dorms or within walking distance in the apartments and houses nearby. If you plan on living away from campus, parking is tough, but there is a trolly line now to campus, you'd just have to live along the line. The dorms were fun for the year I lived in them, but I much preferred renting houses and apartments with my friends just off campus.
Hot people? How about lots of surfers and other athletic guys walking around shirtless whenever the sun is out...which is often.
My suggestion is to visit each campus for a long weekend so you can see what it's like during a school day (and Friday is going to be dead at SDSU...we like to start our weekends early...so see what its like on a Monday) and on the weekends when you'll have more time to yourself.