I was looking at some of these bikes on Fab as well. It's a cool site, but most things seem way overpriced on there. More fun to look at than to buy from, it seems.
Aren't all those bikes fixed gear?
For a commuter bike like those, I find $300 to be a pretty good deal. And they come with a flip flop hub so you can set it up to be fixed gear or single speed. I'm going with single speed, as I prefer to be able to coast tho.