I've given up on recovering data- I do have a Time Machine Backup, but there were some pics I imported that aren't on it. Not worth the money to recover, though.
My problem now is that reinstalling OSX didn't work.
Oh, and when I took it to the Genius Bar, they did open it up and couldn't find anything visibly wrong. They successfully booted it up with an external HD, so they think the HD is probably the problem.
I'm thinking I will have to buy and install a new HD, but before I do that, I thought I'd see if any of you Geniuses had any other ideas.