Colorado is one of the oddest trending states around and one that really just does not fit any model (no matter how much people on this site want it to).
After being heavily GOP during the 1970s, during the mid-1980's Colorado trended heavily Democrat, moving towards the mean as compared to national Presidential results (in 1988 and 1992, Colorado voted right at the national margin of victory for Bush 41 and Clinton) and electing a number of Democrat Senators, including the imitable Gary Hart and Ben Campbell. Maybe Massachusetts Democrats do well in Colorado. 
Then, during the mid-1990s, Colorado shifted right back to its former GOP model during the 1970s and before, electing conservatives Bill Owens as Governor and Wayne Allard as Senator. Campbell also switched parties.
In 1996, Dole performed nearly 10% better here than nationally and in 2000, Bush performed nearly 8% better here than nationally. These compared very strongly to Reagan 1980/1984 (8% and 15%, respectively) and Ford 1976 (13%) and Nixon 1968/1972) (8% and 9%, respectively)
Now, in 2004, the state suddenly shifted back to its mid-80s/early 90s pattern, electing a Democrat Senator, bringing in a Democrat House and Senate (maybe, I forget) and voting just right above the national margin of victory for Bush).
What will 2006 bring? Which Colorado will show up? Who knows?
Looks like it was the Democrat Colorado who showed up in 2006 and it will be that way in 2008.
