i just got a 6.0 off of dogfunk a month ago for 30$. Its really durable thus far, tons of room, looks really good and doesn't have skate board straps hanging everywhere. Not to mention its really comfortable and has a built in pencil case (NERD so its really good for class to class.
Dakine Heli Pro Dlx 20L...it's the shit. Very durable, lots of features, convenient, you can put a looot in there (for example if you're going away for the weekend you can put clothes in there that can last you 4 days) and even when it's empty it's not big and bulky...I love mine.
Dakine heli pro can hold big maps/handbooks without a problem and its one of the better backpacks for actually carrying skis, the sideways postition of the skis is however something you either love or hate .....
only obvious downsides to me are: you're much wider, so watch out where you walk
and if you have a full backpack the skis will crush the stuff inside if you want them tightly attached....
other than that i love it, it's also much easier to get on a bike / snowscooter