I have long held that Obama has the best chance of any candidate to get a staggering total like 58-60%, but also has the best chance of going down in flames. (In stocks, we would say Obama has a high Beta), but Clinton is a "low Beta" candidate, with a somewhat better chance of winning overall, with less chance of an historic blow-out. Obama has a higher potential ceiling, while Clinton has a higher floor.
So I was amused to see the floor-ceiling metaphor pop up in this pretty good Matt Yglesias blog entry about Mike Huckabee's astonishingly bad polling. (Note that the hated Hillary has the same "never vote for" number as the supposedly beloved McCain):
One problem with Jim Pinkerton's optimistic take on Mike Huckabee's electability (and he's by no means alone in this regard) is that in the real world Huckabee seems to be very unpopular. Check this out from the latest CNN / Opinion Research Corporation poll (PDF), for example. Of course if that's bad news for Huckabee, it's terrible news for Romney. I think the best face he could put on those results is simply that it's extremely implausible any nominee could possibly do as badly as this suggests he would. The poll also agrees with my intuition that Hillary Clinton has the higher floor, but Barack Obama the higher ceiling of the two candidates and that John McCain is hard to beat but by no means a shoo-in.
http://matthewyglesias.theatlantic.com/archives/2008/01/open_minds.php