Upgrading from Raptor RAID to Velociratpor RAID?

Currently I'm running a pair of 74GB WD Raptors in a RAID 0 Array for my OS & games, and a pair of Seagate 500GB 7200RPM drives in a separate RAID 0 for storage. Unfortunately 148 gigs is rapidly proving to be inefficient for my purposes at this point as I often have to uninstall an old game to install a new one.

I've been planning on buying a pair of 300GB WD Velociraptors and putting them into a RAID 0 to replace my current raptors. I've been doing a little research on them and came across a utility for HD performance diagnostics. I ran a benchmark on both arrays and came up with some surprising results:

Raptor Array: http://tinypic.com/view.php?pic=9g8ugg&s=6

Seagate 7200RPM Array: http://tinypic.com/view.php?pic=wb9fo1&s=6

That being the case, I am debating using my current storage array (the second link above) to replace my raptors, and buying a pair of 1 or 1.5 TB drives to create a new storage array. I do gaming more than anything on this system (STO, WoW, Mass Effect 2, Dragon Age, MW2, etc) but more than anything want to get the best bang for my buck.

Is it worth the $400 for the Velociraptors with regards to gaming performance compared to the $200 it would cost me to add 2~3 TB of storage to my system and just go with my current 500GB drives for my new OS/Software array?

I am curious if anyone has any specific experience with this. Any advice would be greatly appreciated  

System specs if helps/matters:

Core2Quad Q6600
ASUS Maximus Formula Mobo (Intel x38)
4GB Corsair XMS DDR2 1066
GeForce 9800GT (just ordered dual GTS 250's to replace it)
Windows 7 Ultimate x64