After a fair amount of research I settled on upgrading my motherboard and grabbing an SSD.
I chose the new Crucial C300, and an MSI X58A-GD65 Motherboard.
Once they arrived I quickly updated the bios, and the firmware on the drive, installed Windows 7 x64, and installed Crystal Disk Mark. Immediately, I knew something was wrong. I was only getting 200MB/s reads, and even slower writes - a far cry from the anticipated 350MB/s reads...
After some digging around on the Crucial forum I found another user with the same issue, it appears MSI thought they could get away with putting a 6Gb/s controller on a single 1x PCI-E lane (250MB/s ... ).
I'm obviously very upset, and frustrated. The solution appears to be: Buy an x4 PCI-E controller card.
I've also read some reports that Gigabyte are pulling a similar trick, you can assign a 4x lane to SATA III, and a 4x lane to USB 3, but one of your two 16x lanes drops to 8x if you do this - it's not documented anywhere, people are just figuring it out.