I give him around 15. His campaign is seriously lagging, he's on maybe ten now, with two being challenged, I believe (AZ, IL). He not only has to withstand the litigation and fury of the DNC, he has to withstand the ire of progressive Kerry-voting Democrats and the competition of the Greens and Cobb. He had the resources and support before when he combined the left Democrats, the Greens and others into the foot soldiers and lawyers to get petitions and ballot access across the country. He doesn't have that this year. He's pissed off the activists and organizers who helped in 2000 because they don't want him to run - and those that did wanted him to run as a Green.
All in all, a poorly run campaign. He might make the 19-24 bracket, maybe with a lot of luck up to 30, but ultimately he's going to get screwed. I predict he'll drop out at some point, getting some kind of discussion or agreement with Kerry. He might use Edwards' appointment as VP (if it happens) as an excuse to bail out of this mess he's built for himself. If he takes it all the way to November I don't see him breaking past the 20s, assuming he gets that high.
Only Reform got him this far and they don't really have the manpower, organization or resources to do a whole lot more than a dozen states. They gave him eight state and a step up in a couple others, but other than that they're on their own. I don't see it happening, sorry Nader.
Without the progressives, he's just a regulation-fetishist
without a constituency.