I've been running Vista RC1 (5728) for the last week or so on my main laptop (a Tosh M4), and so far I've been pretty impressed with it.  Perf and stability are both excellent, and I've had no major problems with drivers for my machine (unlike my early experiences with B2).  Not only that, I've had quite a few admiring comments regarding the look of Aero/Glass, which works great on the Tosh, looks rather fetching and is definitely an improvement over the look n feel of XP.

So, I'm planning on installing RC2 in the next few days, and in prep for the update I figured I'd better back up my local mail folders.  I closed down Outlook, and performed a normal file copy of my .pst's into a back-up directory.  Everything appeared happy - EXCEPT - that when I restarted outlook it complained that my Offline Cache file (.ost - where the local copy of my mail state is stored) wasn't a .ost.  Hmmm.. perhaps Outlook hadn't closed the file properly when I was shutting it down... Further checking revealed that the file was definitely corrupt.  Arrrgh!   Last time I looked, my .ost was around 650MB, so a resync with exchange was going to cost me the better part of a half-day give or take a month of Sundays.

Good thing I was running Vista.  I simply used Vista's new shadow copy feature to recover a previous version of my .ost file (that had been secreted away by the O/S late the previous night), restarted Outlook, resync'd changes since the shadow copy was made, and everything was good.

Ok, so I might not have lost the file had I not been running O2007 and Vista (which are pre-release after all).  And I could have waited the eternity it would have taken to resync my mail.  So this wasn't really a mission-critical occasion.  However, I can imagine (in fact REMEMBER) many other scenarios where corrupt/missing files have caused me anguish, and I for one feel a bit safer running Vista (yes, even a pre-release) on my laptop.