Edwards would run in 08 and probably win, doing something noble and fundraising for the DNC would probably be the main way he would pass time....
Meanwhile others events that would probably come to pass would be, Barrack Obama emerging as a real democrat presence in the Senate, Mark Warner perhaps defeating Allen in 06, Harold Ford could also enter the Senate....
As for the other contenders for the nomination they would have to include Feingold, H Clinton (sadly she is a possibility
), Mary Landrieu, Mark Warner, Blanche Lincoln and Ed Rendell would all be potential candidates for the nomination, that said Edwards would probably win easily over all of them with Feingold and Clinton marginalised on the left and (sadly) Lincoln and Rendell marginalised on the right...