I've been extremely happy with my Trek Domane 4.5 and although I was very hesitant to spend that sort of coin on a bike, it's been a huge boost to my comfort when riding. In less than a month's time I've gone from 5-10 mile rides to 45+ mile rides. I've been commuting 30+ miles a day on it and I'm signed up for two metric centuries this month.
Definitely snoop around for year-end clearance deals. I was able to pick up mine with tax/title/license for less than $2000.
If you go aluminum that will shave another $400-600 off the price. I mainly "splurged" on the Ultegra/105 mix because I knew that if I loved it then I'd probably ride it for a while. My last bike was retired after 15+ years of service. I even went so far as to slap a Garmin 510 on it with the ANT+ cadence/speed sensor that's recessed into the chain stays on the carbon model.
I encourage you, as with any bike, to go for an extensive test ride. I love mine but another poster is in the process of selling his as it's uncomfortable (for him) on distance rides. The "bouncing seat post" concept might not be for everyone but it's held my 250+ pound frame on it. As a matter of fact, I was 293 when I first rode it and I'm now down to 276 (after 7 weeks of exercising) and the bike has handled me just fine.
I did shelf the Bontrager 'race' wheels and put some much more meaty 32-spoke H Son wheels with 105 hubs ($275 on eBay) as I was concerned I'd be too heavy for the lighter wheels.