First of all welcome to the forum.
As just going through buying my first road bike as well, I will give you some advice that you didn't ask for:
1. Go to your LBS
(Local Bike Shop/Store
) and talk with them about prices, models, etc.
2. FIT is the most important thing in buying a bike. If you buy a really nice bike, but your back and neck hurt because it is too big, it will not make you faster, because you won't ride it. So don't just say 54-56, either is good. Ride a lot of different bikes until you find one that fits.
If you are sold on buying a bike with out riding it
(which is what I did
) there are some websites that offer good sizing tools.
3. Buy the bike with the best components that you can afford. I had a budget of $250 for the bike, so I had to go to Ebay and got a nice Aluminum Raliegh with Tiagra components for $179, but I wish I could have got at least 105s or Ultegra. Buy better now. It costs more to upgrade later
(IMHO
).
4. Budget at least $200-$300 for pedals, shoes, helmet, jersey, shorts, accessories, pumps, etc
5. If you buy a bike from somewhere other than your LBS, go and get fit on the bike once you get in. It is worth the price that you pay for being properly positioned on the bike.