Timbuk2 - Phoenix Cycling Backpack - looks like a good fit for a rider that carries a lot of stuff regularly. U-lock can easily be slipped into the front pocket and all of the seams and bindings look really durable. 33L at $110.00
ReLoad - Charcoal Waxed Canvas Small Flight Pack - a Philly brand that I am very familiar with. The quality and construction on these bags is top notch. Not totally convinced on the straps on these (though they look a lot more durable than earlier releases) but the waxed canvas has me intrigued. 1110 cu in. for $240.00
Manhattan Portage - Hiker Backpack - I threw this bag into the mix because it is simple, handsome and can easily go from a cycling bag to work bag to hike bag. Features aren't too fancy, but it's simple and has some mega packing potential. $165
Ortlieb - VARIO QL3 - Bang for your buck here. Hi-vis color pattern and completely waterproof shell. Oh, you forgot your clip on fender? Sun shower catch you off guard? This bag'll save your stuff. $160!
Mission Workshop - The Vandal - The one I am considering most highly for my daily commute. I need a lot of room and generally carry an extra outfit in my bag. Plus school books, food, and work things. 4,000 cu in! This bad boy is weatherproof with a lifetime guarantee. $295 though, ouch!
As you can see I'm on the hunt for a new bag for commuting on my bicycle. If you have any suggestions, I am all ears!