Networking is extremely important for your career. Many of the connections I've made and bonds I've formed with people who will likely be able to help me in my career (and I likewise for them) have been formed over more than a few beers at a restaurant or college party. I'm a pretty career driven guy, but to be honest, after you lineup your first job, most employers could give a rats ass about your grades.
I don't find that to be true. I have more of a social life at my top ranked graduate school than I ever did at my less academically recognized undergrad. My graduate program is significantly more intensive and difficult than my undergraduate program as well. A healthy social life and good grades certainly aren't mutually exclusive.
Absolutely agree, but college isn't all about going to class and getting a 4.0. It is an experience that should have a balance of making sure you do well in your classes and engaging in a moderate social life. If I could go back and do undergrad again, I would worry a hell of a lot less about my grades, because they really aren't that important - I would have ended up at the same grad school and same job with a 3.7 GPA as I did with my 3.94 GPA. In grad school I've taken the approach that it is more about learning than about getting all A's - I've learned more and had a hell of of a lot more fun doing it.
As for how you should choose a school - visit campus and see where you feel the most comfortable. You're going to be living there for four years, you'd better like the city and the campus. Talk to as many students as you can and see what they say about the school. See how involved career services is in helping you find a job - let's not forget that, unless your parents are paying for your education, you're probably going to be paying loans when you graduate; a good career services would be helpful in helping you find a job to make those payments. Look at the cost and scholarships available - in general, I personally wouldn't recommend getting into severe debt, especially for most bachelor's degrees.
Finally, and perhaps most importantly, check out the caliber of ladies on campus. Having attended all private schools in Southern California, I'm pretty used to having a lot of "hotties" on campus - it is definitely a plus.