depending on how heavy you ride, i'd recommend a 1.0 tire. i've had great success with ritchey "tom slicks" at 100psi. if your commute route is smooth, you'll really reap the benefit of an almost treadless tire.

unfortunately, my routes changed a bit and i found myself riding rougher, pitted streets with a lot of debris to ride over. i've since changed to specialized "nimbus armadillos" at 1.5". knock on wood, i haven't had a flat in over 6 months. i've also religiously kept the tube at the recommended max of 100psi. the tire is *a lot* heavier than most slicks, but balancing a drop in speed vs lots of flats, the reliability wins out.

for the record, my ATB commuter bike is ~27 lbs., me being between 175 and 185. the armadillos have kept me a very happy commuter.

-chris