Being in the Windows Server group I’ve been runing interim builds of W2K3 SP1 for a looong time. I even have it running on all of my servers at home. In addition my main workstation at work is an AMD Athlon 64 machine running Windows XP Pro x64 Edition which is derived from the same code tree.
I have to say I was skeptical about how good a job we’d be able to do of ensuring application compatibility while still moving forward to a full 64 bit OS (on the client).
I have been dogfooding XP Pro x64 since July and have been completely impressed by the lack of incompatibilities. Most of the things I’ve had to deal with were driver issues. For example, it took a while for Intel to get a x64 version of my SATA RAID controller driver out. The only problem I still have is I have CrystalFontz LCD display that uses USB and there are still no drivers for it.
The only two apps I have that do not currently work are Ultramon and Maxivista. The Ultramon people are working on it (I have a beta x64 version) and the Maxivista people think I’m nuts for even suggesting they do a x64 version.
All games I’ve tried, including Half Life 2, have worked flawlessly.