I don't believe any of the crap that comes from PPP anymore.
CO is minor heavy in Adams, Denver, and parts of Arapahoe county. Check out some of the older neighborhoods and see for yourself (pre 1970s homes).
Colorado has been drifting D. The Romney campaign must go to heroic efforts to win Colorado... OR win some state that has been assumed stalwart D but has been drifting R and is nearly ripe for the picking. Just look at the 2010 election, which should have been a big win for Republicans in Colorado.
Rasmussen is right and has the state as a virtual tie, PPP has the state on the fringe of contention, or else Colorado is weak D.
It is safe to say that Colorado is one state that went for Dubya reliably but has turned on any legacy of his policies. Such happens the other way, too -- think of Arkansas, Tennessee, and West Virginia, the sorts of states that used to be reliably D in all but R landslides but that went R about twelve years ago as the political culture has changed.
Mitt Romney can win Colorado, but for such to happen he must force a nationwide shift in voting in his favor or President Obama must endure some political calamity that nobody can foresee. Romney may be consolidating the vote that went for Gingrich, Perry, or Santorum in the primaries, but that will not be enough with which to win in November. He must basically take back the demographic of the old Rockefeller Republicans who are well-educated, liberal on social values, center-leaning on economics, and hostile to crime. Reagan and Bush won those in the 1980s... and Romney needs them back fast.
Much of that is just not true. A state that Gallup places at 18th in terms of Republican self-idenitification, and a sizable +5 active registration advantage, does not at all indicate a drift left. The GOP had its nadir in Colorado in '06, but it's actually been gaining considerably since then. Results were somewhat split in '08, more GOP-leaning in '10, and '12 could actually be a 2002-esque year for Republicans in Colorado, who have finally, finally, finally gotten back on the horse after the surprises in '04 and '06. The mainstream media/Team Obama narrative that Colorado is inevitably drifting left isn't really borne out by the facts.