Anyone ride a fixed gear?

I am getting more and more interested in a fixed gear bike as I read more about them, particularly as my commute is on a relatively flat path so I rarely need to change gears, and I hear that fixed gear bikes are pretty light, which is a plus. Any downsides to this that I am not aware of? It is hard to transition from a regular bike to a fixed gear?

I watch a lot of fixed gear riders commuting, and see issues. Because there is no coasting (and often, no brakes), they often will run lights, swerve through traffic unpredictably, and split lanes just to keep their momentum. I actually watched one recently, finally stop for a red PERPENDICULAR to the flow of traffic and the direction he was headed. Then, a bus went out to pass him, cut back too close, and essentially took him down (BTW - the buss cut too close because it would have hit MY CAR if it didn't).

That all said, you might consider a singlespeed. Same idea, but with brakes, and you can coast ;). I have a couple of these, and LOVE them - both on the road and on the trails. You can also get a flip/flop hub that allows you to have either a SS, of a fixie.

SheFly

You can also put a fixed/free rear wheel, with a flip/flop hub on the bike. That lets you decide if you want to run the bike as a fixed gear or with a freewheel, just by turnig your rear wheel around. I contemplated doing the same but, I really want to tour so, I went with a different bike.

I took my first ride on a fixed-gear yesterday afternoon... had been looking for a bike to convert for bike polo, and found a very nice deal on a used fixie from my LBS.

There's no coasting... so you need to look ahead and plan your stops, as well as take turns a lot more gently... you can't coast thru the turn and there's a risk of the pedal striking the ground if you lean the bike too far, and knocking you off. With that in mind it was a pretty nice ride...

I'll be adding a freewheel to it, as well as a rear brake and some slightly lower gears.

I get to borrow a single-speed at times, and I just love it. I ride it where the terrain is fairly flat, and the gear is fairly low anyway, so I don't miss having gears. It feels like being a kid all over again: want to go faster, pedal faster! I love being able to coast, so I've never flipped to the fixed gear side on the bike I borrow.

I bought a steel single speed from bikes direct cheap for my farm road ride in Georgia. That thing is a BLAST! No gears, just pedal and coast when I need to.