I can hold four 2 inch binders, a book, and my pencil case in the big pocket and my lunch in the small one. It does not feel very heavy unless you loosen the straps a lot. If you want more size I would go with:

Borealis: http://www.amazon.com/The-North-Face-Borealis-Daypack/dp/B0089RQY06/ref=sr_1_1?ie=UTF8&qid=1401494903&sr=8-1&keywords=Borealis

Recon: http://www.amazon.com/dp/B006CVVD7A/ref=twister_B000KWDTBK

Big Shot: http://www.amazon.com/The-North-Face-Daypack-Black/dp/B003U8FMSY/ref=sr_1_2 ie=UTF8&qid=1401495124&sr=8-2&keywords=Big+shot+north+face

Hope this helps!