You mentioned he's looking for a desktop replacement. What specifically is he intending on doing with this computer? Does he know what his major will be? How much travelling with it will he be doing? How long we'll he be away from a power socket?
Toshiba, IBM, Dell and Apple would be where I'd focus my interest. I also really like the very slimmed down Sony's but Sony is quirky and they're "desktop replacement" models aren't terribly competitive. I also tend to believe that if you want a portable computer, the focus should be on portability and not a perfect replacement for a desktop. You can get very powerful laptops that will pretty much do anything a desktop can but their battery life is non-existant and they're heavy as hell.
Talk to the school's bookstore, though. Most colleges have cut deals with one provider or another and they will be significantly cheaper than any normal purchase.
