Warning: since build 7127 x64 (I don't know if the same problem happens with x32 version) the latest asus xonar d2 vista 64 (Version 6.12.8.1764) completely breaks windows seven !
It installs fine, then reboots, the operating system seems to boot fine but once on the desktop you can't launch any application.

Solution: use msconfig in safe mode and prevent "HsMgr.exe" & "HsMgr64.exe" from starting with windows. You'll lose the EAX emulation in games.
Another solution (the one that I choose) is to reboot in safe mode, uninstall the driver, reboot again and install it "manually" (by the device manager/update driver/browse to the .inf ).
The driver is here:

Asus audio center won't load anymore, but the driver seems to work fine (you can still access/manage your audio levels/inputs/outputs by right clicking the volume icon on the taskbar).
There's a topic about it on asus's audio forum.