Thanks for the responses everyone. Yeah, as a little kid riding a BMX I never had a problem being singlespeed. But 20 years of gearing and I don't know if I can handle it anymore. One big thing that concerns me is that my commute to work is all uphill, and I wonder if I can hang. The draw of the singlespeed, of course, is to just do it! I also like how quiet they are and how much less bull I'll have to do in terms of maintenance. I should also note that I live in San Francisco and go to school in Berkeley --- not exactly flatlands. But yeah. I figure I can work my way up to it with a big cog at first and just keep buying smaller cogs as I get stronger!