In a sudden move, Microsoft today released Vista SP1 Release Candidate to the general public.
SP1 was available to beta testers for 6 months and has recently become available to MSDN subscribers.
Clearly Microsoft feels that a drastic move is needed to stem the tide of people reverting back to XP, or (gasp!) looking for alternatives in Linux-land. Otherwise, I can't explain why an RC version, which surely has its share of bugs, is made available to the public.
Here's the latest example I've read today: the new Toshiba T31 will ship with both Vista and XP.
You can read about my test drive of SP1 here, and download it yourself here.