Black Diamond Hollowpoint---I like the old version here more than the new one that is top-loading.
Nice narrow pack, good straps, sternum and waist. It holds a good deal of stuff including my powerbook (12"--not sure if it would fit the MacBooks), a couple books, hat, long sleeve shirt, then in the outer pocket tools and iPod and lots of other assorted junk. This is my favorite bag on days when I don't need the big mess bag.