Gallup:

The political landscape could be improving for Barack Obama in the waning days of the campaign. Gallup Poll Daily tracking from Oct. 28-30 shows him with an eight percentage point lead over John McCain among traditional likely voters -- 51% to 43% -- his largest margin to date using this historical Gallup Poll voter model.

Since Tuesday, McCain's support among traditional likely voters has dropped by four points (from 47% to 43%), Obama's has risen by two points (from 49% to 51%), and the percentage of undecided voters has increased from 4% to 6%.

Thursday night's interviews are the first conducted entirely after Obama's widely viewed 30-minute prime-time campaign ad, which ran on several television networks Wednesday evening. Obama held a substantial lead over McCain in last night's polling, however no greater than what Gallup found on Wednesday.

Obama's current 11-point lead over McCain among all registered voters -- 52% to 41% -- is up from an eight-point lead in yesterday's report, and ties his highest advantage on this basis, last recorded 10 days ago.