Traveling Light
I recently purchased the Lululemon Cruiser Backpack. I've tried several other packs along the way, but this one is my fave. It's waterproof! The pockets are well thought out and clearly labeled with color-coded raised icons and zipper tags. Thirteen pockets hold my Bluetooth headset, cell phone, PDA/GPS, iPod , laptop computer, CD/DVDs, digital camera, wallet, keys, sunglasses, various chargers, and more... Wearing t-shirts and jeans, there's room for two full changes of clothes (plus the ones on my back). It's very well made and has been tested with weights up to 50 pounds.
Rolf Potts in his book "Vagabonding: An Uncommon Guide to the Art of Long-Term World Travel
It comes in green and charcoal grey.
You might also like to read Ross' post on Matador Travel: Traveling around the world with your laptop: not as tricky as you'd think. I think this waterproof pack, with lots of pockets, may be the perfect solution.
Make it to Ireland this autumn: One-Way Flights From $159+