Mosslack, I remember you figured out an issue installing Vista on GUID formatted disks, rather than MBR. Not using your method on a GUID disk would certainly cause problems.
abbzer0- I'm curious if you're trying to install Vista on its own hard drive, and using Vista to format, or the same drive you've got OSX running on? Also, very important to remember- if you're using a seperate drive for Vista, keep in mind that Windows likes to install its bootloader to the DEFAULT boot drive, which may not be the drive you're installing to. So a classic screw up with dual boot systems is to install OSX first- it's drive is set as the default boot, therefore the target drive for the bootloader. You add another drive, don't switch it to default, and begin trying to install Vista to the second drive. When Vista goes to install its bootloader, it looks at the system DEFAULT drive- your OSX disk, and (worst case, overwrites the boot sector on it, or best case, fails, because it can't write to the drive). I've found the best way to be absolutely sure when installing Windows, is to remove the power connectors to ALL other hard drives in the system. The target drive for Vista should be the only drive in the system, therefore, the bootloader has no choice but to install to it, and act completely independent of other system drives. (It's been my experience that when AHCI is turned on in the BIOS, Vista will install generic drivers for AHCI -x86 and x64 versions- or one can install the Intel Matrix drivers from the 'drivers' tab, via a USB flash drive.) Once everything is running, you can then reattach otherdrives, select the boot default in BIOS, and also use the F12 menu to select the disk/OS to boot from.
Hope any of this makes sense, and maybe helps with any install issues. It's ironic that OSX is actually the easiest OS to install on these things- if you think about it, the hardware is MADE to run Vista! You'd think there would be no problems running it.
Eastwind- that setup looks great! Please let us know how the E7AUM-DS2H performs. I'd guess some people are using a graphic card rather than on board for gaming or more intense graphic apps, but really, I don't know why anyone would get an mATX board with onboard graphics for those tasks. So you should be good to go with the onboard, certainly for an HTPC. The Power supply is great- I've used that exact model, very reliable, and the max power rating shouldn't matter as you'll likely never come close to maxing it.