I got the Speck Aftpack as a gift last winter, and it's by far my favorite bag ever.
There are 2 ways to get to your notebook from the backpack, and the padding is thick and fleece-lined. There's definite separation, and little pockets to tuck away extra handles, and that front strap that goes around your abdomen, so it's out of the way.
Not to mention it stands up on its own, looks great, comes in 2 designs, it's really well built (it feels as sturdy as my old targus backpack, which gave me 6 years of faithful service and is still going strong minus 2 small holes), and it has a LOT of room for extras like textbooks.
The only downsides I see are that it is a pricey bag ($100USD [sometimes though, it's really worth the money, as you don't have to keep buying cheaper bags over time]), my 13'' UMB with a speck case fits good, but it's not really snug because it's made to accommodate up to a 17'' (I'm sure if you use something like a sleeve or whatever anyways, it's not an issue. I don't see a huge issue as it still feels safe to me), and it's a large product. Backpacks can be large though, and you can really get away with it. It's very stylish anyways, and I absolutely adore it for the sole fact I can fit my charger, 3 textbooks, 3 notebooks, pens, pencils, my TI-89 calculator, my organizer, spare packets of coffee, a water bottle, a notebook in its case, my MP3 player, cell phone, and digital camera in there without a problem.
Something I did that could be really useful is if you don't use the abdomen straps (I know they're great for reducing back pain, but I can't stand them), cut them off, and you have 2 great little pockets for things like your cell phone or gum. There are no side pockets so these become handy.
http://www.speckproducts.com/products/aftpack-backpack/notebooks-up-to-17/170