I just did a conversion to fixed gear from an old Schwinn Traveler. I found a Mavic wheel set and Sugino crank set really cheap in the local classifieds from a former messenger and some handlebars his friend had lying around. The chain line isn't perfect but other than that it's been great for my commute. The whole thing cost me a little over $200 and I got some experience putting together a bike. Hills were rough at first, but now I enjoy the challenge and the simplicity of the climb. I do something like 13 miles round trip with a 200 ft climb (the hill is 3 or 4 blocks long) and really enjoy it.