Fixed wheel (no coasting possible) single speeds are elegant, light, athletically challenging, and sensually pleasing to ride--quiet, smooth, and even compared to a well-maintained geared machine amazingly free of drive train drag. Hope this doesn't sound like Shirley MacLaine-oid crystal jerking, but they connect you to your riding environment more directly. You feel and have to deal more immediately with changes in grade, wind, and even pavement quality. As a side attraction, they are of course much lower maintainance bikes than a contemporary geared bike with too many gears, ultrasensitive shifting, and rapid wear designed into parts with anorexically skinny chains and preworn, I mean ramped, cogs and chainrings. It is interesting that there is a small but growing market in dedicated single-speed bikes now--Surly and Soma, for instance--whereas 20 years ago the only interested parties were track racers and Schwinn balloon tire collectors. I absolutely believe that there's a link between a demand for simpler bikes and the excess of shifting technology in contemporary geared bikes. BTW, a super-bargain when you find one is a Schwinn Madison, a US-made entry level track bike from the mid-1980's. A friend of mine scored one for his wife for $75!