i feel i should apologize before i even write this, because it seems so silly.
i received a phone call and e-mail today from ucla today informing me that i've been accepted. as seems to be the opinion of most people on this forum, i think that not hearing anything for a while is a good sign and you can infer that they are still considering you for acceptance. it seems the only ones that go out quickly are the instant admits and rejects. i guess i fall into the latter because of my numbers (174/4.0), but i know that ucla can take a particularly long time to decide, as they jerked a loved one around until bloody august last year (in fact i'm not sure she ever got final word about her waitlist status, and i don't think she was informed of being on the waitlist until late april or may). usc also took a while to reply to her last year, but accepted her when they finally did make a decision.
i'm not sure what your numbers are, but given the schools you've gotten into (particularly northwestern) i imagine you have a rather good shot at getting into usc or ucla (or, hopefully, both).