I scored one of those Wald paperboy baskets for$20 on CL. I LOVE IT!! It slips right over the Blackburn rack that's already mounted to my bike and then I cinch it down w/bungees. Mine's on backwards, though, so it fits better. I also have a blinkie bracket bolted to the bracket that would mount the basket to the bike frame. I could throw a pic up if you want, but I'm supposed to be doing schoolwork now

It holds tons of stuff: gallon milk jugs, 12-packs of beer, college textbooks, what have you.