I'm really interested in buying a new single speed bicycle or fixed gear and throwing some brakes onto it. I've looked around a lot online and a few bikes that caught my eye are:

Torker U-District
Windsor Hour
SE Draft

My budget is $250-350.

I want to know your honest opinion on what I should get. I'm open to other options. Right now I have a 1974, 10 speed Schwinn Varsity. It's a nice bike, but the shifters are tough to move and the bike itself is a tank... (37 lbs!) I was wondering what you would do in my situation?