The ocz vertex 2's look nice but I would just raid some velociraptors for now if you have money for that kind of thing.
A PCI-E SATA 3.0 controller card performance compared to onboard would depend on the quality of the part.
I wouldn't wait for SATA 6 Gbit/s hardware and buy on release since prices in this sector tend to plummet more rapidly than others.
I'm waiting for SATA 6 Gbit/s, minimum 500gb, £159.
Maybe in a year?
2500K 4.7ghz,P8P67Pro,120gb Force3, 8gb Vengeance,R9290,TX850v2,W7HP,LaCie Blue 22" crt COMMODORE 64 Silver Label 1Mhz/128D 4Mhz(Z80)