Since Public Policy Polling is conducting a poll of Virginia this weekend, I thought I'd check their blog. They have a post "Was Obama's approval ever that high?"
They have an interesting take, since their numbers on Obama's approval have been between 50% to 55% since March. Gallup had better numbers throughout the spring for Obama, but now he's at 50% on their poll and 52% in Public Policy Polling.
So, is Obama's popularity stable or falling? Either the town hall protests are having a big impact, or those who pushed Obama's agenda in the spring were vastly overstating how many people actually wanted it.
Time will tell, but you can't look at all the different polls and use the best to help your position.