When I pull all-nighters (or, as is more often the case, get only ~2 hours of sleep), I'll usually feel surprisingly awake and alert for the majority of the morning. However, once early afternoon hits, I'm going to crash...and quickly.
As for how much homework to expect in college, most professors will tell you to spend anywhere from 1-3 hours preparing outside of class for every hour that you spend in class. However, as LoKe said, it varies drastically from person to person, and from major to major. Here in grad school, it's closer to a 10/1 ratio at times.