I am riding my ultimate commuter.

Gunnar Streetdog singlespeed, here are the highlights (I won't bore you with a slavish recitation of every single part):

Gearing 42x16 (easy enough to race away from a stop light without standing up, it doesn't spin out at speed and I don't really have any really steep hills on my commute to worry about)

Phil high-flange track hubs laced to 700c velocity fusion rims (stiff, durable wheel, sealed bearings are a must)

Cantilever brakes (this used to be standard on the Streetdog until a few years ago when they switched to longer reach calipers)

Drop bars with Cane Creek levers (if you aren't married to STI levers, try these, they are shaped like the Campy levers so they are really comfortable)

Full fenders (during the rainy season only)

Sometimes a rack and panniers, mostly not. I like the loads I can carry with panniers but like the handling without them.

This is my favorite bike because it is simple, reliable, easy to maintain, comfortable, STEEL, takes corners like a dream and it is a blast to ride. There is lots of tire clearance on this bike so it takes knobbies and doubles as a great bike for SS cross racing or bombing down fireroads.