I like this one because I really don't know how it would turn out. Guiliani would run as a tough forgein policy canidate, which is an issue than trancends party lines. Edwards would run as a populist, getting good support from those who are worried about the economy and their jobs. This kind of issue also can garner support from both sides. Both are pretty liberal when it comes to social issues, so it would be interesting to see where the usual Bush crowd breaks.
The outcome? I think the Democrats continue their drift towards the center, and win in a strange result, Edwards the clear favorite going into election day.
The pre-election map.
and my best guess on the actual result
Edwards 333
Rudy 205
I just think the political atmosphere will still favor the Dems, especially if they continue to drift towards the center. Plus, not having a socially conservative canidate run (or at least someone who can be percieved as one), I believe would kill the GOP in its current state. I don't think Rudy can win a general election.