I've seen Senate polls featuring Warner vs. every Republican alive in VA, and Warner trumps them all by a ridiculously large margin.
See this Rasmussen poll released yesterday, for example:
Former Democratic Governor Mark Warner’s lead continues to grow over former Republican Governor Jim Gilmore in Virginia’s race for the United States Senate. The latest Rasmussen Reports telephone survey in the state finds Warner on top 59% to 33%. Last month, Warner enjoyed a 57% to 34% lead.
When “leaners” are included, the Democrat now leads 61% to 35%http://www.rasmussenreports.com/public_content/politics/election_20082/2008_senate_elections/virginia/election_2008_virginia_senateWarner has also the approval of most Virginians for solving a big budget crisis while he was governor.
When it comes to being experienced and popular, I doubt anyone tops Warner. Plus he's from the state that is perhaps the most important swing state in our sight.