Why won't Blagojevich resign?

It's not as if there's any hope of his staying in office, after all.

Presumably, he's just holding out for a better deal.  But from whom?  Fitzgerald has him dead to rights, by all accounts.  He loses nothing by an impeachment.

This article available online at:

http://www.theatlantic.com/business/archive/2008/12/why-won-apos-t-blagojevich-resign/4471/