First of all, let me congratulate anarchist420 for finally posting a thread that is both interesting and not from some alternate universe.
Ron Paul is an astute and experienced politician, he knows that any third party campaign will torpedo any chance whatsoever the GOP have of winning the White House. But he also knows the GOP won't take the White House anyway with the incredibly weak field of candidates and wackos they have running. OTOH he also may not have too much allegiance to the GOP left and be thinking it's time to replace the national GOP with a new libertarian type party.
I put no weight behind his claims he's in the Presidential race to win, they all say that no matter how hopeless.
There is also the big question as to whether Paul, as a third party, could poll enough to get into the Presidential debates and on the ballots in all the states. Fanatical Paulbots may not believe their messiah is not adored by all-in reality he only draws well under 10% of the general electorate. He's no Ross Perot, much less a Teddie Roosevelt.
I don't think Paul wants to be another Ralph Nader spoiler, but it is possible he will run on a third party/Liberatarian Party slate.
For the Dems it would be the next best news to a Palin or Bachmann as the GOP nominee, so I hope he goes for it.