I just put a deposit down on a new bike made by Redline, model 925 (read "nine-to-five.")
It's a single-speed urban commuter, cool geometry, nice road tires, fairly light, cromoly. You can flip the wheel over and it becomes a fixed gear bike.
I commute 16 miles each way to my day job, and was doing that previously on an entry-level aluminum Trek mountain bike (with road slicks and a straight fork that i put on.) I gradually became very frustrated with that ride for many reasons.
Anyhow, The Redline looks like it was very well thought out and seems to be well built. Certainly felt GREAT on the test ride! Since this will be my first single-speed (adult) bike, I'm banking on a paradox a knowledgable mechanic once described: that the single-speed is actually more efficient than a multi-speed bike (in the right conditions)...having dispensed with the weight of the derailers, shifters, cables, extra sprockets & longer chain, in conjuction with the gear train running straight from spocket to chain wheel. Additionally, I must admit, the Redline single-speed has a Zen-like appeal to me.