mine would have to be Genarts Sapphire. www.genarts.com
i tried it sometime ago using avid xpress dv 3.5 and it blew my mind off. it was a huge, complete and mind-boggling set of plugins for video ever. it costs a lot though. but i doubt it will be really available for vegas, they seem to serve high-end video currently like discreet, quantel and avid.