Neither will help you in game. However, the answer is by far the SSD.
SSDs are an order of magnitude faster than VRs. In addition, the newer 500 GB platter drives (Samsung Spinpoint F3 500 GB/1 TB, Seagate 7200.12 500 GB/1 TB and Western Digital Caviar Black 2 TB) are just as faster and much cheaper/GB. The Samsungs and Seagates are $55 for 500 GB or $90 for 1 TB, the WD is $300. In addition to being cheaper and faster, these drives are also quieter, run cooler and use less energy.
To sum it all up, VRs are completely obsolete. Cheaper drives are just as good and much larger. Similarly priced SSDs are many, many, many times faster. They really have no place in any build right now. If you don't already own some VRs, don't buy them.
That said, there are problems with SSDs too. First, they're really expensive. Second, they like to have a lot of empty space to work to the full potential. Third, they don't like to have constant rewrites, making them bad drives for actual data. Fourth, they're new technology and still getting the kinks worked out.
They would both give you the same FPS. I would completely forget about the VelociRaptor drives. They are yesterday's technology and the current 7200RPM 500GB platter drives are faster for much cheaper. If you're looking for the fastest load times, then the SSD is the way to go. I don't know your budget, but I would just go with a Samsung F3 drive and put the money saved toward a more important component.