Ok I currently have a Trek 1000 which Ive used for about 4 years now. Great purchase because it was inexpensive and it really got me into the sport of road cycling. Now its time to upgrade. the options I'm considering are:

-2008 Scott CR1 for $1600 (Great price, good reviews, brand new)
-A 2006 Trek Madone 5.5 for $2000!! (Great price, better bike, great reviews, Used, owner claims only has 75 miles and hes moving to a place where a mountain bike would serve him more)
- A new Madone ?.? probably a 5.2 or higher (expensive, new bike, newer technology)

So what do you guys think? What would be the real differences say between a Madone 06 5.5 and say an 08 5.5, consider the fact that I would be paying $2000 more. Thanks in advance for the help!