I was recently pointed to this site by a friend in the UK. Just for the purposes of clarification:

1) There is nothing constitutionally to prevent a former president from being vice-president. In fact, Gerald Ford was seriously considered for Reagan's running mate in 1980. Even with the unexpected demise of the president, the 22nd Amendment would not stand in the way of the former pres/current VP from assuming office. The amendment forbids a person being ELECTED president more than twice, but says nothing about him being able to serve in that capacity if he is not elected to the position.

2) McCain is a Republican, and very unlikely to change parties, so his likelihood of becoming the Dem. nominee in 2004 are negligible.

3)Although Jeffords left the GOP, he did not join the Dems. He's also pretty old, so he'd be an unlikely choice.

4) I don't think there's any way the Dems. would nominate Nader, nor Nader join the Dems. after what happened in 2000.

5) Daschle is a possibility, as is Gephart, especially if the Dems. take the House in the 2002 elections. However, the nomination is probably Gore's to lose. I've already seen bumperstickers on cars here that state "Re-Elect Gore in 2004."