I've got a Raptor for Windows, games and apps, and a 7200 drive for storage.
I couldn't be happier with it. It gives me speed and redundancy - I backup very important data from the 7200 to the Raptor, and the Raptor makes a very significant difference running Windows and games.
RAID is one of the most oversold gimics in motherboards these days. There are very few instances where it is useful. RAID 1 is useful for live backup's, but easily countered by proper backup procedures (i.e. external hard drives). RAID 0 is useless unless you move GBs and GBs of data constantly, work with huge video files, content creation, or the like.
1 Raptor and 1 Large drive is perfectly fine and you will feel much more of a difference from a Raptor as compared to a RAID 0 array. Raptor has a faster rotational speed so seeking is faster and transfer is faster than a single drive, RAID 0 is the same rotational speed so seeking is the same as a single non raptor disk, but transfer speed is greatly increased (unnoticeable unless you play with GB files daily).
cheers, i was thinking it over with friends and im going to go Raptor and big 2nd HD.
I currently run 2 SCSI drives - and I run my software on 1 drive and my 2nd is storage, Ive always liked being able to make a backup of the software and OS install, so I can clear the 1st drive if need be.
Maybe im wrong but ive always thought that the primary OS and software drive takes more punishment from use then my 2nd drive, so if it does fail, as its used more, im not gonna lose my work, only my software setup, which is easier to stomach.
really important data I back up to an external HD.