I gotta say I'm really surprised to read these posts. After two years in law school, my take on it is if you want a BigLaw job, then as a 1L you'll be going hard from about 8AM-9PM all year, and studying most of the day on Saturdays and Sundays too. If you do that you'll finish pretty high in the class.
If you don't care, then the 9-5 might work but I still doubt it; I don't know a single person who did that. However, I wasn't at a T-14 so maybe things are different at that level...not all of us score a 170 on the LSAT.