People really like the CAAD frames. CAAD10 5. Felt F75 looks to be comparable. So does the Trek 2.1. And Specialized Allez Elite. All around $1500 which will get you a very nice 105 bike. Pick your price point and then look to see what bikes offer 105 component set. Ride and decide. If you read around the Road forum, you can find good bikes at decent price that are not from the mega manufacturers.

Your finances sounds tight. The most responsible action would be to get a $1500 Aluminum/105 bike (2011 models are on sale if you can find one you like in your size) and put the other $1k you would spend on carbon frame in the bank for a rainy day. I see too many Craigslist people desperately trying to sell expensive bikes for food.