I'm finishing up this semester with Microbiology and already feel the need for a nice, durable rolling backpack (something to carry me through nursing school too). I like the ones on "e-Bags.com" but I'm not sure which one I should get. I know I need one with alot of space and I'd like one with plenty of room or pockets for other things such as keys, snacks, etc. Any suggestions would be great! Thanks!