Depends on how rich you are.
Very rich: get a PCI-Express SSD.
A little rich: get a PCI-Express SATA III controller card. Not one with just x1 PCI-E lane; they can't keep up with SATA III speeds.
Not rich: Do what I did. Attache SSD to SATA II port and experience blazing system performance compared to what you had when you booted from a hard drive.