basically what I've typically done is this
Hook up my RAID array
Create 8 partitions
1 6GB Partition for Windows
1 60GB Partition for Programs
1 1GB Partition for Page File with Page File set to 768MB
1 20GB Partition for eMule
1 20GB Partition for Bittorrent
1 20GB Partition for kazaa
2 15GB Partitons for me and my fiances documents
So with our 2 80GB drives it ended up like that
However you can feel free to do it however you want
