I ride Trek Aluminum Frame / partly carbon Road Bike, for past 7-8 years. I am planning to buy a Full Carbon Bike. I am looking at three bikes as follows:-
Bianchi 105 Infinito ($2700)
http://www.bianchiusa.com/bikes/road.../infinito-105/

Trek Madone 4.7 ($3100)
http://www.trekbikes.com/us/en/bikes...s/madone_4_7/#

Trek Madone 4.5 ($2100)
http://www.trekbikes.com/us/en/bikes...s/madone_4_5/#

Most economic for me would be Trek Madone 4.5 ($2100)
but it is heavier than above two bikes. moreover I hate this black color.

Trek 4.7 is way too expensive for me .. but that depends what I am getting, I pay for that..! Bianchi I never used, so please suggest me your opinion.