As someone who used almost exclusively Debian, Ubuntu and free software on my desktops and laptops for five years, I have to say that some aspects of the culture surrounding them has been turning me off recently. Spreading the word is fine, but do we really need a bunch of trolls posting ill-informed knee-jerk b.s. (in the sense that they don't really care whether it's true or not) on every *ing MS-related story on every blog?
Another thing is that a lot of the FUD around Vista is about the same things as the FUD around Linux -- basically compatibility, familiarity and not wanting to have to deal with limited user accounts. I guess you could say turnabout is fair play, but after five years of frustration at the Linux FUD it kinda bugs me to see the same stuff applied in the other direction.