Yeah ... my recomendations for SpireUSA and Timbuk2 we're because I have two bags from both of the companies but they sell multiple quality bags which you should look into on your own. I own a smaller messenger bag from timbuk2 which is excellent and fits my 12" powerbook and maybe like one book. From Spire I own the Volt XL, and it is pretty massive. I have never had trouble fitting everything I need into that bag. It expands and contracts and even the compaartments can usually hold a book or two.
One of the biggest features you should consider is the mateiral they are made out of. This is for two reason, to protect against rain, and for durability. My friend greg used his odler backback and the second day of school it downpoured all day. He runed his $150 calculus book and it lost most of its reslae value all because of a cheap backpack. The biggest problems with my bags and liquids we're my fault when a water bottle was on the inside and opened but even then, it was in a seperate comaprtment usually.
Also consider how comfortable the bag will be with these big loads your expecting to carry, because you need to find something thats well engineered so that carrying all your stuff wont' kill your back.
So pick your price range, but keep in mind that the backpack not only needs to carry a few large books, it needs to protect your laptop, books, and other stuff which you don't want ruined from weather. $1500 for a laptop, and $400 for books per semester = $2300 which shows why it might be better to spend a little extra ...
