I think a good number of the responses here are from 0Ls, as is this one.
I think you will get sick of the North East very quickly coming from L.A. My sig-o and I relocated from L.A. up there for a while so I could take a job. I am from that part of the world and knew what to expect. She always thought snow was "pretty" and was game for the adventure. After one winter up there she doesn't want to ever live there again. YMMV.
Geography and weather aside, the definite best option for you is USC, clearly. USC is highly regarded in SoCal, and spending your law school years in the area will help you network.
The following is not merely 0L advice, but advice from someone with years in the "real world" prior to pursuing law school: jobs (at least well paying ones) will often present themselves in locations where the location is a secondary consideration to the type of job being offered and compensation. What this means is if you go to school in Boston you may very well wind up taking a job wherever you can find one. Navigating your way back to Southern California may prove difficult, for the reasons that have already been covered ITT (proximity and networking, degree portability, bar issues, etc).
Stay in sunny SoCal. Go to the higher ranked school with a strong reputation in your stated desired market. Live in somewhere other than South L.A. and put on your blinders between home and campus. Take a vacation to Boston or NYC this summer and make the most of your time, all the while realizing you are there on vacation and not really living "real life." Go again for a week or two over your winter break, preferably during some really miserable weather, to witness the bullet you just dodged. Your welcome.