advice
hi jessika,
i bought a single speed bike in december 2007, the genesis flyer. if you are getting a single speed, then go for one with a flip flop hub that will allow you to have the option of riding fixed gear or free wheel.
best is to get measured up to find your exact size as fit is everything. i test rode the genesis flyer, the charge plug, the bianchi pista, the le mond fillamore and the kona paddy wagon. my budget was £500 sterling and went for the genesis as they made my frame size of 52.
any questions then just drop us a line.
hope this helps.
sebastian