Bart De Smet yesterday shared some Longhorn milestone dates, for anyone who's keeping track. RTM of the client on 24 May 2006, apparently. Personally I found it more interesting to hear that WinFS might be backported to Windows XP
Well, SP2 installed just fine on my XP Pro laptop (which is fairly crufty and full of beta software and assorted junk). No problems or unexpected side-effects to report as yet.