Be very very careful installing the optional PROMISE AHCI Raid Driver that Windows Update started pushing out to Windows 7 64 bit yesterday or the day before on an ASUS P5K-E based system, and perhaps other systems that might use a similar controller (JMicron controller in this instance). Doing so on one of our work system causes the system to BSOD on the next boot.
Fortunately, we don't boot from that controller, so we were able to use Windows 7 recovery options for "easy" (if a bit "scary") recovery. I have to say that Windows 7 is MUCH better than XP in that regard, although what would have happened had that controller been connected to the boot drive, I can't say.
Anyway, thought I'd mention it here, as I know that the P5K-E is fairly popular.
<S>
P.S. In case it matters, that controller is set to IDE mode in BIOS on this machine, and is attached to a DVD drive only - no disk drives.