if you are planning on using vista 64 with your 4gb of ram, then you MUST buy an OEM version of vista64, since you can't upgrade from 32bit to 64bit. but if you are sticking with 32bit, then you could buy the upgrade, but it would be a pain in the butt to reinstall the upgrade if you ever needed too.
IMO, i would just buy the oem version regardless of 32bit or 64bit.
If you buy the Ultimate upgrade you will get both 32-bit and 64-bit DVDs in the package. You may not be able to upgrade a 32-bit OS, but the 64-bit DVD will allow you to perform a clean install over 32-bit XP. The upgrade process will stick your Documents and Settings folder from XP into a folder called Windows.old. Other than that, your install will be squeaky clean.
Interesting, would it be faster if I took my old 160GB hard drive, and set it in a RAID with my 500 GB?
That would give me two 320 GB drives.
Can I then install Vista on the stripped drive, and then mount my User profile directory into the other 320GB drive?
That way my program files are put in a RAID, and all my personal data is on a safer disk.
For the Most part, I agree with Zanny, however if you wish to use the spanning feature, or the Remote Desktop feature, you need to use Ultimate. I dont know if the 64 Bit version has these features but the 32 Bit does not. Ive run into that problem with Home Premium. I am currently running 3 320 gig Hard drives and wanted to span a Volume but found out that it was a feature not included in Home Premium