So I got myself a basic rear rack for my lightweight XLC panniers (which are these things, more or less):
http://www.amazon.com/Xlc-Expedition...s=xlc+panniers

...and the only issue I have with them, once they're loaded with my U-lock, laptop, and a couple of other items, is how much harder it is to walk the bike or stand it up without it "jackknifing" on me. The ride itself is fine....