McCain seeks to delay debate so that he and Obama can go back to DC and discuss bailout plans with other leaders.
On the one hand, I would generally prefer that Congress only be in session 2 months a year (preferably July and February, because I think they are the most miserable times to be in DC), and so I find it hard to advocate congress sticking around to clean up this mess. As a default rule I prefer congress not trying to fix things to congress trying to fix things.
On the other hand, there's some serious legislating about to happen, and the idea that our elected leaders are gallivanting about the country trying to secure offices, perhaps higher offices, instead of doing their jobs is a bit galling. It's distasteful in the way taking time off work before a big deadline to go job hunting is.
On the gripping hand McCain has never indicated before that he's willing to sacrifice campaigning for actually doing his constitutional duties, so I have to think this is 100% naked political stunt designed to send the message that he cares more about the plight of the economy than the other guy.