I really like the Brain Bag/Brain Cell combo. I used it for a weekend conference the first week I got it, which was just a couple months ago. Had the Macbook, a couple large books, several MP3 player/recorders, accessories for the electronics, DSLR camera, and other stuff in there.
If longer-term user reports mean anything, this bag will probably outlast most everything inside it. Very well constructed. Their accessories are expensive, though. I have another $100 of stuff I want to buy from them. The $50 Brain Cell sleeve can be used on its own, though, unlike most sleeves. Nice if you don't need everything else occasionally. This was what actually drew me to Tom Bihn, and I ended up getting the backpack, too.