Ok I've been thinking this over. What if Gore decided to go for OH Instead of FL, narrowly wins it, W. picked Pataki or Engle to broaden his base, campaigned hard in MI, IL, NY, NJ, and PA, narrowly loses all of them, but it's enough to win the popular vote? He refuses to allow a recount to divide and weaken the country so concedes before recounts. This makes him look like a graceful statesman to the people and he's generally well-liked. He campaigns hard for the GOP in 02, 04, and 06. Could he make a comeback in 08 in a President Gore/Lieberman TL?
I think it would have been Hard for Bush to make a 2008 comeback like the one Nixon did in 1968. The reason is that Bush was only on the national stage for the 2000 election, and would have been forgotten by 2008. You have to remember, Nixon was a rising star in the Republican party while in Congress, and was a two term Vice President. Bush was merely a popular govorner.
If Gore had bowed out graciously after the first Florida recount, I think he could have made a 2008 comeback. I think he would have been the favorite for the Democratic nomination.