So far I think all the recent noise about Al Gore is just sound and fury signifying nothing...I can't see him defeating Hillary for the nomination if it comes down to those two. The Left is unhappy with Hillary because of her occasional moderate rhetoric which they should realize is just a sham to fool voters--she's as much a hard-line leftist as any of them.
2008 is indeed her best chance, and even if she loses, she still has the Senate seat, and control of the party for the next four years.