Things that have surprised me most about biglaw:
1. How many e-mails I get. I usually get 100+ by the afternoon. And then, b/c you're tied to e-mail 24/7, your Blackberry is constantly dinging/buzzing even when you get home.
2. Partners really will call at 5 p.m. on a Friday, just when you think you're set for a nice weekend, and give you an assignment due on Monday morning.
3. Overall, it's not so bad. I think that between classes, homework, and ECs in college and law school, I probably work fewer hours now.