UAD-1e Express Pack at AudioMidi.com for $99
Apparently Audiomidi isn’t the only place with this deal, but it’s an insane price. It lists at $499, and Audiomidi regularly has them at $299. At that price, you can buy more than one, and the drivers support up to 4 in one system.
This is a SHARC based hardware accelerator for running VST audio plugins. I tested both a UAD-1 PCI and a TCI Powercore for Grooves Magazine years ago and thought the UAD-1 was killer.