I’ve been needing a new bag for work/school. During the school term, I carry both school and work items on the bus – i.e. books, notebooks (computer and otherwise), pens, calculator, lunch, etc. All that stuff adds up to a good sized load; a robust bag is important. I went ahead and picked up a bag from Timbuk2 – the Commute XL. So far, I really love it. It’s thoroughly water-proofed, with a solid rubber bottom and rubberized inside. It’s got a padded sleeve for the laptop and a nice broad strap. It’s a little on the pricey side, but considering the durability built into it, I suspect it’ll last for quite a while.