Salazar's district -- which covers roughly half the state, from Grand Junction to Pueblo -- is a pretty conservative one. The same year that Salazar won that seat, Bush beat Kerry in that district 55-44. My feeling is that last month was the high water mark for the Democratic surge. From this point on, Democrats begin to be perceived as the party in power and start taking some heat for their decisions and the condition of the country. The odds of Dems holding onto Colorado's 3rd CD are pretty good if Salazar stays in office. They're considerably weaker in an open-seat special election. I'm surprised the party is considering this.
I'm not convinced we've witnessed the Dem high water mark in Colorado. There's not much more we can win but I think underlying demographics play heavily in Democrats favor. More specific though to the question of Salazar I am in total agreement with Seth's analysis. Presumably former state Joint Budget Committee chairman Bernie Buescher would be the Democratic candidate and one would guess that state Senator Josh Penry would be the Republican candidate. Given the conservative nature of the district and the fact that the powerful incumbent Buescher was just ousted in a shocking upset I'd put good money on Penry winning that race.
Obama was actually pretty competitive in the 3rd CD. I haven't totalled up the numbers (and neither has the Secretary of State) but glancing at the map Obama won 2 of the 3 major population centers, Pueblo (Pueblo County) and Durango (La Plata) and lost in Grand Junction (Mesa).