I mentioned three weeks ago that I had just repaved my work dev box and installed the 64-bit version of the Windows 7 RC. Nine or ten years after I first ported parts of IIS to Win64, I am finally running my main desktop on 64-bit Windows. With one exception, it's been painless. Programs have just worked, devices have just worked. There are relatively few native x64 applications, but for the most part it doesn't matter. The cases where it does matter—e.g., shell extensions such as TortoiseSVN—are available as 64-bit binaries.