I converted an old, light-weight steel Nishiki criterium bike to a fixed gear last year after reading Sheldon Browns articles on the benefits. However, I only ride it weekends on the flat roads of Delaware and take it on vacations to relatively flat areas. At 57 I'm a little concerned about overstressing my knees on the short-but-steep hills around here in SE Penna. However, I do enjoy the change and agree with most of the reasons that others give for riding a fixed. I especially love the quiet ride and the feeling of being one with the bike. Also, I hadn't thought about it before, but I certainly agree with what was said here about riding more efficiently into the wind. The seemingly ever-present winds on the Easten Shore can make you long for windless hills, even mountains! If you have the opportunity to try a fixed for at least a few weeks, I would highly recommend it.