The L.A. Times poll referenced by Isaac below is interesting data, in part because it confirms my preconceived notions (which makes it the best kind of data.) For one thing, it shows Fred Thompson surging close to the lead in the GOP field, which is what I expect. (If I had to bet on who will take the Republican nomination, I'd bet on Thompson.)
Second, it shows Hillary Clinton with a massive electability problem. In a general election trial heat, she runs behind Giuliani, McCain, and even Mitt Romney, who up to this point has been getting crushed in any trial heat. John Edwards runs better than Clinton, crushing Romney, edging out Rudy Giuliani, and losing narrowly to John McCain.
The Democratic candidate who fares best is Barack Obama. As the L.A. Times puts it, "This poll shows that Obama, among the top three Democratic candidates, appears to be the more electable candidate." No kidding. Compare Obama's performance to Clinton's against three GOP contenders. Clinton loses to McCain by 4 points, Obama wins by 12. Clinton loses to Romney by 2 points, Obama wins by 16. Clinton loses to Giuliani by 10 points, Obama wins by 5.
In other words, he runs 15 to 18 points ahead of her in a general election. Give whatever caveats you want about polls and the election being a year and a half away, this is an important finding. I've seen all sorts of anecdotal evidence of independents and moderate Republicans being open to Obama and hostile to Clinton, and it's starting to show in the polls.