Is there such a thing as good spyware?

It seems Microsoft thinks that there juat may be. Or atleast, spyware seems to be doing a good job of masquerading as legitimate software. See their analysis: Windows AntiSpyware (Beta): Analysis Approach and Categories. One of their (IMO valid) points is that the failure of a software package to validly indentiy and later remove itself is a good clue about its 'evil' intent.