Here’s a really bad scenario. House Republicans give-in/lose on those taxes now (which they probably will do as they expire) and then in 2016 voters perception is that the economy improved under Obama, meaning Republicans are not able to sell the case that those higher taxes hurt the economy as they been claiming they would.
Another scenario, some of those taxes go up in January as O appears to win a standoff and the economy crashes (for whatever reason) and Republicans have an issue for 2012.