I run cheap 26x1.5 slick tires on my commuter. Better than my 26x2.1 tires for winter, because lighter (also no tread, but that's a different story). Having a tire, that is rated for 85PSI(+) is nice, my front tire is only 65PSI and I sometimes wish I could go a bit up. There are also 26x1.25 tires, but matching tubes are sometimes hard to get.