I have a SwissGear by Wegner computer backpack that I'm very happy with. It's one of the larger models and holds my laptop and accessories, a change of clothes packed in an Eagle Creek packing cube, a few filefolders, and other travel necessities, and has a sleve on both sides for water bottles. This backpack has an incredible number of very handy pockets and compartments inside and out to help me stay organized. I got mine at Best Buy on sale, here's a link to a variety of models:

http://www.buy.com/store/wenger-swis...ags/58703.html

I have this model:

http://www.buy.com/prod/synergy-15-6...6234/10393071.