I'm using the Zogby Interactive Poll from 10/19 (McCain has been surging since, for what it's worth), since it's a more reliable poll than most. Jim Zogby is an open Democrat and a solid pollster.
In none of these states does Barack Obama have greater than a 3.6% lead according to Zogby, which essentially puts them all in serious play. It's important to note that the last-second undecideds may often flip toward McCain in many of these states; not only are they red-leaning states, but people will either prefer a steady hand over an inexperienced one or will not wish for a liberal supermajority (White House - Senate - House of Representatives all blue).
- Colorado (9): Obama +0.3
- Florida (27): Obama +3.6
- Missouri (11): McCain +0.3
- Nevada (5): McCain +7.5
- New Hampshire (4): Obama +0.3
- New Mexico (5): Obama +0.6
- North Carolina (15): Obama +3.1
- Ohio (20): McCain +2.8
- Virginia (13): Obama +3.6
McCain can lose either Virginia; Missouri; Colorado + New Hampshire; or any two of NM, NH, and NV and still win. He can lose all three of NM, NH, and NV or CO and NM or NV and still tie.