Are there any people out there using any of the various plugins from Video Copilot [Twitch, Evolution,, Riot Gear - etc.] with either After Effects CS3 or CS4 under the Vista 64bit OS environment?

I have Twitch running on CS3, in both 32-bit and 64-bit Vista Ultimate without any problems. Riot Gear and Evolution aren't really plugins- they're just a bunch of pre-made elements that you can incorporate into your designs and projects or to come up with something from scratch. I'm not sure about Twitch off hand, but you should be able to use everything from the Riot Gear and Evolution packs even if you're running an older version of AE. Hope this helps.