Steve Bullock
Public Policy Polling (PDF). 11/28-30. Montana voters. MoE ±2.4% (6/16-19 in parentheses):
Steve Bullock (D): 38 (37)
Rick Hill (R): 39 (39)
Undecided: 23 (23)
Steve Bullock (D): 42 (38)
Jeff Essmann (R): 30 (33)
Undecided: 28 (28)
Steve Bullock (D): 41 (--)
Neil Livingstone (R): 29 (--)
Undecided: 30 (--)
Steve Bullock (D): 40 (38)
Ken Miller (R): 31 (34)
Undecided: 29 (28)
There may turn out to be some gubernatorial races in 2012 that eventually turn out to be closer than Montana's contest, left open by two-term Dem Brian Schweitzer being termed-out. (The Washington race is likely to tighten once low-info Dems start paying attention; the West Virginia rematch could be close if Obama reverse-coattails sink Earl Ray Tomblin; New Hampshire could be anyone's ballgame.) But polling suggests that, as of this moment, this is the closest gubernatorial race, with likely nominees Democratic AG Steve Bullock and Republican ex-Rep. Rick Hill consistently a point or two apart.
Bullock, like Sen. Jon Tester (who's also up in 2012, and very narrowly trailing in PPP's polling), is a well-liked figure, pulling in 34/17 favorables. That's substantially better than Hill, who's at 22/27. However, Bullock is up against the state's distinctly Republican lean; it looks like there are enough Republicans who either like Bullock, don't like Hill, or both, who will still vote 'R' to give the slim edge to Hill.
Interestingly, this doesn't seem to extend to the lesser-known Republicans (Hill is the only one who has held statewide office before, in Montana's at-large House seat); Bullock has significant leads over the miscellaneous state legislators and businessmen in the field. Don't get your hopes up for Hill losing the GOP primary, though, especially in light of his big name rec advantage and non-Hill vote-splitting in the overcrowded field ... PPP polled the primary too and found Hill at 37 to 10 for Ken Miller, 5 for Jeff Essmann, 4 for Jim Lynch, 3 for Neil Livingstone and Jim O'Hara, 2 for Corey Stapleton, and 1 for Bob Fanning.
Similarly, Bullock still has to emerge from the Democratic primary, but he's in even better position in that two-man field, leading state Sen. Larry Jent by a whopping 70-6. If Jent somehow finds his way into the general, he loses to all comers (39-26 to Hill, 33-25 to Miller, and 30-26 to both Livingstone and Essmann), so our strength here is purely Bullock-based.