Whats the best software/configuration option?
Linux has good hard drive performance on its own and its bound to be slower running on top of windows. There is no hypervisor that lets you do windows gaming in full which I care about so thats not an answer I'm looking for. I have separate hard drives that linux can use exclusively, and raid is also an option.
If your Windows box has room for at least 5 drives, you can put windows on 1 of them and use the other four drives for RAID 10 and use the RAID volume for storage of the VM files for your Linux guest. If you have tape or other backup mechanism and don't want to invest in 4 additional drives, you can try RAID 0 across 2 drives. You'll still want your OS on a separate physical drive than where you store your VM guest.
If you've got CPU cycles to burn, software RAID should be just fine (i.e, a quad core or dual quad core system). Generally, VM guests want as fast a disk sub-system as you can give them; the more/faster spindles the merrier.
In terms of virtualization software, I would recommend VMware Workstation.
Virtualization doesn't mix well with gaming. There is not much discussion about this. The only decent hypervisor solution running on top of Windows is Hyper-V and that doesn't support 3D graphics.
Virtualization is an entreprise feature mainly. If you're going to be gaming, stay out of virtualization :-)
You can eventualy have Windows whatever and a Linux Virtualbox, that should work fine, nice and simple.