For what it's worth, I'm a rising junior at a 'top' schools.... dunno if that makes my opinion any more useful to you than it would be otherwise, but there you go...
I don't know much about the new SAT scores, but if I just scale them linearly down to the x/1600 scale, you're running a little low there. Not so low that they won't look at you, but still.
I'd consider retaking SAT2 physics as well unless you have an AP test for it (AP-C, AP-B means nothing).
GPA is also hanging a little low, but I've seen lower where I go to school.
Do you have any APs?
The fact that you're taking college classes (at a pretty good school no less--WPI) will help, *greatly*. Colleges look on that kind of thing very highly, according to my admissions office. Actually, Cornell loves the college classes too; I spoke to their head of admissions about it (~3 yrs ago)--I had multivar calc, difeq, linalg at NC State.
If the community service was more or less all in 1 or 2 places, it'll do you a lot of good. But the more spread out it is, the less it helps you.
Crew is nice, but the fact that you stopped after soph yr won't help you as much as if you'd followed through.
CMU & Cornell & other ranking engineering schools like math competitions. MIT is an extreme example, but their application has places to mark your scores for the more famous contests. Their admissions "grade sheet" also has boxes for performance at various competitions... even the IMO.
The drama/creative writing stuff will be useful to you. Schools are into this whole "well-rounded" stuff these days and so working in technical/creative areas will play to your advantage.
Oh yeah... teacher recommendations help too, and you NEED to pick wisely. Here are some characteristics to look for if you haven't thought of them already... they 1) know you, 2) have solid writing ability, 3) have some other neat credentials (I had one of my professors recommend me). But the knowing you well thing is uber-important. Colleges don't give a damn about teachers who can say like "yeah he was a good student, did well in my class, contributed to dscussions..."--everybody can get that. What they want are some specific examples that illustrate your stronger character traits.
Do a GOOD job on the essays. They're important. "Everybody" says so (well the offices I've talked to at least). If you feel like you're BS-ing, start over. Admissions officers read so many of those things that the 'canned' ones are glazed over... but they remember the good ones. (And on the essays that ask "why do you want to go here" or similar, go the the school webpage, look up professors/programs/etc, and write about them. Don't say anything like "b/c it's a top school in _______ field"; stating the obvious makes you look lame.)
Lastly, if your school(s) of interest do alumni interviews, do it! They're almost always voluntary, but you should do it. And if the application has some optional bits (MIT has an extra page on which they ask you to do whatever you want), you should do those too--shows you give a damn & is a place to show the school anything not covered in the app.
For other schools: UIUC, UMich-Ann Arbor, PennState--Univ Park. I considered those three in addition to Cornell, CMU & MIT in hs. I didn't look to the west or the south, but there are good schools there too (Stanford, Berkeley, Rice, GA-Tech, and others)
In summary: Your tests/GPA are the low end of things. A whole year of classes at WPI will help. Being "diversified" (e.g. drama) for more points; community service a plus only if it isn't spread out over 10 random projects.
In my estimation, you have a shot at CMU and Cornell. If your college grades come out well, that will help. If you have strong essays & recommendations, that will help even more. With all of that in place, you're probably about middle to middle-upper of the pack in my opinion, b/c I think you'd have enough going for you to balance out some of the weaker bits. But if your essays suck or your recommendations are lame or whatever, then I'd gander that your chances drop off a bit.
So in other words, you're riding the fence & you need everything you can get, but it's far from a lost cause.
Edit: in response to something above, 780 on mathiic ins't near perfect, at least not when I took it. The way they grade it, you can make like 5ish mistakes and still get an 800. That's why I got an 800 on that but not on the SAT-math.
And for reference, I disagree with some of the things said about CMU. Some of their engineering programs are VERY strong (esp EECS), but they don't admit quite like "top tier" schools but also not like "second tier" schools either... they're in the middle. Illustrating example: I had a friend visit their campus/stay a few days & many students he spoke with said they ended up at CMU b/c they were rejected from MIT. That's not to say that CMUs program is any weaker, but more that their admissions standards aren't quite as stiff. (B/c well, as a relatively new school (reputation-wise) w/o a whole lot of money... yeah you get the point. And that's coming from an ex CMU professor.)