It was a couple of years ago when I finally decided to get of my 20kg mountain bike and started looking around for a good roadie.
I drive around alot with work and called into all but a few bike shops in and around Sydney which made my head to spin (options, types, price etc).
The best advise Ireceived was from experienced riders who just loved to ride more than the love of the bike.
It's true that a good roadie starts from $800 (when on sale). I was told that carbon is not required but carbon forks and stays do help over bumps. I was told by a few trusted riders that 105 gear sets are a very good start and even OK as entry level into racing.
The most useful advise I received was to buy at the end of the year (if you can wait that long) and look for the run out models or previous models that the bike shops are trying to move to make way for new stock.
Unless you have a disposable income I strongly believe it is not necessary to pay more than $2000. I ride with a good group and some of the quickest guys ride the cheapest bikes ($750 - $1700).
One rider doesnt even have a full carbon frame....OH MY GOD

Just when I was going to compromise on quality I found the bike I really wanted at the price that I (MY WIFE) was willing to pay!
If you are like me and a little obsessed with maintance it will last for ever.