Just had the shop true my wheels and install a set of Kenda Kwest 700/35 100psi tires. I know there are even better tires out there. Previously had a 700/40 85psi hybrid tire. The difference in rolling resistance is dramatic. You can now pause on the pedals and coast 50-60feet & start right up again. Before if you stopped pedaling, you better be grabing a lower gear. We ride a limestone and so far no problem with traction.

Only down side is now I have to buy another set for my girlfriends bike! Also I can't seem to find the 100psi ones listed on the typical mail order places. Her bike is new so the wheels should be fine. Figured I could put a set on it myself.