Well, something with a NEC/Renesas chip on it should do the trick. Just make sure to get the latest driver (v2.1.36)...
PCIe USB3 cards are pretty similar anyway you look at them, you should just go for the cheapest one you can find. But make sure you get one with a powerplug (SATA or Molex) on it, otherwise you can run in to problems with some peripherals that draw more power then the card can supply.
Speed wise you should remember that the hard drive is the weakest link, but it should net you a reasonable upgrade over USB2... 🙂