For commuting you really cannot beat the flat-proofity of the Specialized Armadillos. They run a bit more (about $45) but are all but flat proof. I'm an assistant manager at Rochester's largest bicycle store and have heard nothing but rave reviews on them. They actually have a kevlar casing in them!
If you can't quite spring for em, try out some Serfas Drifters. At about $25 they are the next best thing as far as flat protection is concerned.