Hmm, there are some good LAN games like Age of Empires, or Crimson Skies. You still try to whoop on each other, but it's a lot different than your standard fps. But you know if you go to them or not.

I don't think you need a PCI RAID card at all... if you have it built into the motherboard, why not use it? Same controller on it (pretty sure anyway). Perhaps use a pair of (same size) smaller hard drives on the RAID channels for your OS, running RAID 0, and another bigger hard drive for your file storage and your backups?