Rasmussen has some interesting numbers on Sarah Palin:

Sixty-nine percent (69%) of Republican voters say Alaska Governor Sarah Palin helped John McCain's bid for the presidency, even as news reports surface that some McCain staffers think she was a liability. ...

When asked to choose among some of the GOP's top names for their choice for the party's 2012 presidential nominee, 64% say Palin. The next closest contenders are two former governors and unsuccessful challengers for the presidential nomination this year -- Mike Huckabee of Arkansas with 12% support and Mitt Romney of Massachusetts with 11%.

Despite that, I would not say that Palin is the 2012 GOP frontrunner. With these kind of things, voters have short-term memories. It really all depends on what Palin does over the next year or so, as well as what Romney, Jindal, Pawlenty, Sanford, etc., etc., do.