Who would have won the biggest landslide vs McCain?

[Canis]

Obama would have done better in the EC and the popular vote but Clinton would have done a lot better in the south and Appalachia I see her winning MO and AR but losing IN and NC she also would have come closer in KY and WV but I think she would have picked Obama as VP and those states were trending so republican she probably still doesn't win them but it could be enough to bring down Mitch here's what I think the map would look like  Clinton was very popular in AR back in 2008 she wouldn't carry it by a landslide like the polls showed but I think she would have edged

[Canis]

What about between Richardson, Biden, Dodd, Kucinich and Vilsack?

All of em would have won (besides Kucinich maybe I don't hate the guy and I would have supported him in the primary after Gravel dropped out but his views are a little weird how they range from Conservative to Progressive and some of his views might have been looked at as too extreme for 2008) just because things were so bad for the GOP that year but I only see them doing significantly better in their home states none of them would have energized turnout like Obama or Hillary did.