I would say Eli Manning, Tony Romo [now hurt], Kurt Warner, Drew Brees and Jay Cutler are your early faves. I don't think any of those guys is that far out in front right now.
Why did you exclude Rivers and Favre?Rivers: 6 games, 3-3 record (but should be 4-2), 102/165 (61.8%), 1489 yards (9.02 ypa), 14 TDs, 4 interceptions, 8 sacks, 109.4 QB rating
Favre: 5 games, 3-2 record, 112/157 (71.3%), 1124 yards (7.16 ypa), 13 TDs, 6 interceptions, 12 sacks, 103.0 QB rating
Brees: 6 games, 3-3 record, 159/224 (71.0%), 1993 yards (8.90), 12 TDs, 6 interceptions, 6 sacks, 105.0 QB rating
Warner: 6 games, 4-2 record, 149/213 (70.0%), 1708 yards (8.02 ypa), 12 TDs, 5 interceptions, 13 sacks, 102.8 QB rating
Romo: 6 games, 4-2 record, 128/200 (64.0%), 1689 yards (8.45 ypa), 14 TDs, 5 interceptions, 7 sacks, 103.5 QB rating
Cutler: 6 games, 4-2 record (but should be 3-3), 146/228 (64.0%), 1694 yards (7.43 ypa), 12 TDs, 5 interceptions, 2 sacks, 94.8 QB rating
Eli: 4 games, 4-0 record, 84/132 (63.6%), 1032 yards (7.82 ypa), 6 TDs, 1 interception, 5 sacks, 99.7 QB rating
IMO Romo will fall out of consideration due to his injury (and he also suffers somewhat from the better supporting cast argument... others will be looked upon as doing more with less).
Eli has played 1-2 fewer games so far... IMO it is a bit premature to put him in this group.
McNabb, Roethlisberger, and Campbell were mentioned, but there is too much better (so far) competition at QB IMO.
Not making the playoffs will probably knock at least a couple of the guys above out of contention.
And, finally, you have to ask what teammates might be viable candidates themselves, and thus draw votes away from the QBs? At this stage, I'd say Romo (Barber), McNabb (Westbrook), Eli (Jacobs), Campbell (Portis), and Brees (Bush) might all suffer to varying degrees due to that factor.
IMO Brees, Favre, Rivers, and Warner (in no particular order) are the strongest contenders at this point.