At your height you would probably get a road bike somewhere around 54 - 56cm or MTB 17-19".

If you are looking to go fast than probably a road bike would be your best bet. So either the Schwinn or the Ross in your link. From the looks of it, he is selling some nice bikes. For your price range you are looking in the craigslist, used, pawn shop, garage sale, auctions, and etc. type of markets.

Trusted brands are the Trek, Specialized, Giant, Cannondale, or any bike usually sold in a LBS. For your price range they me be out of contention.

First off You pretty much know what type of activities you will be doing with it. Second you know your price range. The next step is the most important, making sure the bike fits. The measurements I gave you previously are rough estimates. Some people like bikes a little larger or a little smaller.

Basically go for a test ride on as many bikes as you can in your price range. Get the one you are most comfortable on and will use.