I'm a beginning photography student, and I'm looking for a bag. I've got a 600D with the 18-55mm kit lens and a 50mm lens. What I'd like to find is a bag that I can carry those in and have them protected while at the same time having some storage space for some school supplies as well (pens, legal pad, spiral notebook maybe a slim 3-ring binder). I'm looking for either a sling or backpack type bag, something close to a Clik Elite Impulse sling.. Ideally, I'd want a sling bag with easy access to at least my camera and storage for a notebook (of the paper variety) of some sort. However, I'm pretty sure said ideal bag doesn't exist.

At bare minimum:
Backpack or sling
Padding for a 600D with kit lens
Non-camera storage

So with all that in mind, does anyone have any suggestions on where I should be looking or what I should be looking at? I appreciate any sort of help.