The performance difference among all modern hard drives is minimal. Do not expect to see much difference.
For performance, get a SSD with a sandforce controller. Do not be misled by the sequential transfer speeds which are advertised.
Do not bother with raid-0 either. Synthetic benchmarks have no bearing to your access pattern, and are meaningless.
You want a drive with the best 4K I/O capability
I think I would get the crucial C300:http://www.newegg.com/Product/Product.aspx?Item=N82E16820148357