Polls, polls, and more polls over the last few days, and they uniformly paint a bright picture for Sen. Clinton, and a dim picture for Obama/Edwards/rest of the candidates.
CNN - national primary- Clinton 46%, Obama 23%, Edwards 16%
CBS/NYT - roughly the same numbers.
The LA Times is out with new polls in the early three states (IA, NH, SC) which show Clinton climbing. RCP link (LATimes is subscription only).
If Hillary! can pull out a win in Iowa, it's over for the rest of them. If she finished second but wins NH and SC, it's over for the rest of them then too. It's hard to envision a scenario in which she loses this nomination.