The new ABC News/WaPo poll has some interesting nuggets. Obama beats McCain by twelve, and Clinton beats McCain by six. What accounts for Obama's bigger margin? Well, men prefer him by three points to McCain, and prefer McCain by seven points to Clinton. But, more noteworthy, he does three points better against McCain among women, suggesting that he can pick up Democratic women if he wins the primaries (it's also worth pointing out that the percentage of women who vote in Democratic primaries is higher than the percentage of women who vote in general elections).
The other major discrepancy is among non-evangelical white protestants. Obama does 14 points better with Clinton among these voters (my hunch, for somewhat obvious reasons, is that this group includes a lot of independents).
Two final points: first, Clinton has had a great few days, and if she can maintain this momentum these numbers will close. Second, she does fine with black voters (although Obama does better, I'd expect Hillary to pick up more and more support as memories of South Carolina fade). This evidence, combined with Obama's success among key Democratic groups, signals to me that either candidate will be able to consolidate Democratic voters in a general election match-up. If this is true, independents are key.