I've got a Timbuk2 Swig, just picked it up a couple of months ago. I dig it. I had a Timbuk2 medium laptop messenger bag for almost a decade before that. I'm actually not using the bag quite so much right at the moment, I just did another commuter rebuild and am using a rack and panniers. It's done a great job of reminding me how much I hate what a pair of panniers does to the handling of a zippy cyclocross bike. On the other hand, the sweaty back thing is kind of annoying in the summer. For a while I was rocking a big Wald front basket on a different bike, and that was pretty good, but more than a couple pounds in a front basket on a bike not intended to carry weight on the front wheels and things get pretty unpleasant. So pretty much everything is some kind of compromise. For three seasons out of the year, I think I lean toward the backpack, provided it's designed for wearing on a bicycle.