Here is my theory:
Regardless of whether Clinton, Obama, Edwards, or (possibly even) Gore becomes the presidential nominee...I feel any of them could benefit from Richardson as their running mate. Richardson has a ton of experience and is from the West. The 2008 Democratic National Convention will be held in the Western state of Colorado...a state which borders New Mexico...the state where Bill Richardson is governor.

Here is a quote from Economist magazine shortly after the 2006 midterms:
"Republicans suffered big losses in a region that voted solidly for Bush in 2004—the Mountain West. Three Republicans lost house seats. Conrad Burns lost his Senate seat in Montana (59% for Bush in 2004). Democrats now control five of the eight governorships in the West, compared with none in 2000."