I'd look at an iPad. You cannot beat the battery life, which is important for ALL DAY lectures.
The iOS and I assume Android offer interesting apps which allow note taking while recording audio in real time. Some will argue that there are laptops/netbooks which can do the same, but my counterpoint would be, not without plugging in, which is sometimes difficult in the middle of a large lecture hall. I remember those who used laptops would generally already have all the plugs taken at the beginning of lecture. Some schools
have revamped their lecture halls to include individual plugs, but not in all rooms.
My other point, weight. Again, the tablet cannot be beat, whether iOS or Android, lugging around a 5+ pound laptop begins to take a toll, depending upon where you have to park. Add that on top of the huge books you already have to carry and well...you get the point.
Good point about the cloud.
I'd shy away from the netbooks. Windows 7 starter is just not comparable to either iOS or Android.