.MASSHOLE.You basically have two types of frames, endurance and aero. Aero frames are bikes like the new Trek Madone 9 series, Specialized Venge and Cervelo S Series. These frames are obviously built for their aerodynamic profiles which in turn can result in less comfortable positions (some would argue otherwise). Endurance bikes are bikes like the Trek Domane, Emonda, Specialized Roubiax, Allez, and Cervelo R series. These bikes have a less aggressive profile (better for riding longer distances) and have a gentler ride (again, some would argue otherwise).
Aero bikes are mostly used for racing but you will see some people who purchase them just because they look cool. I imagine you are on a budget so now is a great time to go purchase a bike. Shops are looking to close out any left over inventory from 2015 bikes and will have some on sale. Take a test ride and see what bike you like. They are all different.
This is all true, good advice, however there is also a third category: lightweight (example: Trek Emonda). Basically it comes down to
Aero road bike: Good for going fast on flat terrain, good for going fast into headwind, good for breakaway sprinters. Examples are Madone, Venge
Lightweight road bike: Good for going fast uphill, good for racing in mountainous and very hilly areas. Examples is Emonda
Endurance road bike: Good for very long rides, good for racing on rough roads i.e. Paris-Roubaix but other than that not ideal for road racing. Example is Domane