I agree with bossk about the being targeted thing, part of the reason i like my backpack and suggested it. Unfortunatly while on campus this wasnt the situation cause everyone had one, though if they had the laptop in it is another story.
The nice thing with the kelty (and jansport to some extent) is that it has 2 compartments, so you can have books in the other. they both also have a padded section where the laptop goes. The kelty also has the ability to take that section out completly and the part where it connects to the bag can then have a strap attacthed to it and can be carried as just the laptop (not all that usefull really (at least imho) but it taking it out lets you use it as a regular bag (which you can do with it in, but you get a bit more space when its out) )
-Darth Simon