Nader’s thinking he might run again.
It’s a bit hard to see him playing his 2000 spoiler role again. He was essentially a non-factor in 2004, getting one half of one percent; I suspect he would have a hard time matching that, unless the Democratic nominee had some sort of major flaw to the liberal base. If John Kerry could keep the Deaniacs, Hillary, Obama, or Edwards seem likely to keep the Green-leaning Democrats.
In related news, Pat Paulsen ran five times; this would be number four for Nader… No, wait, he got about 6,000 votes as a write-in candidate in the New Hampshire primary in 1992.