After riding the fixie for a while, I recently switched over to a singlespeed to spice things up. I have to say I like it better.

1. You can coast. You can also stop better. More wear on the tire. Healthier all around.

2. No "cheating". It's a freewheel, so You actually have to pedal, instead of relying on the momentum to carry you on flats.

3. More maneuveraribility in traffic. Brakes+coasting helps turn corners fasters.

4. You can fly down a hill without killing your knees or looking like a doop.

5. You get more athletic working your way up a hill see #2.

6. Simplicity, with the added bonus of not having to worry about lockrings.

7. You don't resemble a hamster in wheel, and your bike looks like a stripped down road bike, not a mutated "tarck" day-glo abortion.