I sent you a PM, Wildside, but I am going to assume you meant the question above...?
what about if i, hypothetically, had Windows Vista Ultimate upgrade on the Raptor, n Windows XP Pro on my other HDD, would it still work? If so, would the OS of Vista run better n faster on a 10,000 rpm then on a 7200 rpm HDD?
As long as you did a clean install of the upgrade, or you just threw your XP Pro away.
You would have a dual boot system. The Vista would run a little faster in things that require accessing the HD due to the Raptor's speed, but run the same in things that are just RAM intensive.
In a RAID0 with two 'Cudas, you could still do a dual boot, as long as the OSs were in different partitions.