Colorado is a state full of political Independents so the GOP is poised to make significant gains there this year with one notable exception: the governorship. Dan Maes, the GOP's choice for governor, is a terribly flawed candidate (both in his personal history and in his mysterious politics) and that, combined with Independent candidate Tom Tancredo running for the post should end any chance the Republicans have for retaking the post. If Maes were to drop out and Tancredo to end his bid then the GOP would have a shot but right now it certainly seems that they will stubbornly stay in the race and lose.
Ken Buck, the GOP candidate for Senate is up a few points over the incumbent Democrat and he should win. Again, the Independent vote should put him over the top.
There are three Democratic House members who are in trouble. Betsy Markey (CD 4) will lose, John Salazar (CD 3), the brother of the Interior Secretary, will probably lose, and Earl Perlmutter (CD 7) is in deep trouble. All three seats were held by Republicans within the last six years and have fairly conservative voters.
In 2004 George Bush carried the state but the GOP's Senate candidate Pete Coors lost narrowly to Ken Salazar and the Democrats captured the State Senate and Assembly. I'm not sure if the GOP can retake both chambers but they'll get a bunch of seats back. If ever there was a year to be a "downballot" Republican this is it.