I think DeFazio will probably run if there is enough financial incentive from the DSCC - that was what kept him out of the race against Smith in 2002. A DeFazio candidacy would probably change the race rating to Toss-up or perhaps even Lean Democrat.
I am starting to get the feeling that he is going to run after all. It's almost like deja vu with current situation with DeFazio and Claire McCaskill and Sherrod Brown in '05. Chuck Schumer is one persuasive guy who can raise a sh**t-load of money and is also extremely politically skilled. I think at least a few of his dream candidates who origianlly said that they would not run (Mark Warner, Jean Shaheen, DeFazio, etc) will end up running.