We have spent 6 months using Windows 2008 x64 and are really disappointed a lot of things don't work. So we are going to migrate back to Windows 2003 32-Bit where EVERYTHING works, IIS Password, Perl, Frontpage, ASP, ASP.Net 1.1, Python, Coldfusion, Access databases, Reboots twice as fast, etc...
It's like upgrading Windows XP to Vista. A lot of things broke, drivers don't work, software don't work. Man do we regret upgrading to Windows 2008. DotNetPanel was awesome under Windows 2003. Everything just kinda crapped out in 2008. Also, another big mistake was upgrading to SQL 2008. More than 1/2 of the applications in the Application Installer are gone. I read somewhere that IIS6 outperforms IIS7. As far as I can tell there is really no reason to use Windows 2008 or IIS7 because there really isn't any new features, just a bunch of incompatible software.
Stick to 32-bit Windows 2003 and everything will work perfectly. It can still handle 8 cores and 64GB of ram (enterprise edition) without having to be on x64 edition. We are switching back this weekend,.HUGE task!!!