This looks like it would be a contender, given the info on hand:
http://s1036.photobucket.com/albums/...t=IMG_1379.jpg

Fit will be one of the biggest factors, and don't assume that speed necessitates discomfort. You height is a good starting point, but how about other proportions? Is your torso longer or shorter than "typical", same with inseam?
If you are of pretty typical proportions, your inseam is probably 30-32" or so, which makes 54-57cm a good starting point for size.

Test ride some bikes, new, used, road, hybrid, etc. Get a feel for what you like. Guaranteed you would get far more enjoyment out of a properly sized but "slower" mountain bike than a poorly fitting "faster" road bike.

Since you are young and interested in more speed, with minimal if any hills, a singlespeed (with a freewheel rather than fixed gear) might be the ticket.