Until I saw some Sandy Bridge benches on encodes, yes. Now...not quite so fast enough. I do a lot video encoding, and while I can leave the system encoding overnight/through the next day, I'd still like to be able to do larger batches, or run small encodes quickly. But in the end, it at least suffices so I don't fall behind on anything.
Gaming wise, however, my secondary (285GTX/QX6700@3.14GHz/4GB DDR2) and primary(460GTX/Athlon II X4 640@3.3GHz+/4GB DDR3) systems are enough. As someone said, with so many high-profile games being ports or multi-platform without PC optimization, there's only a handful of titles can really start to push it. It also probably helps that I'm one of the few people who DOESN'T like antialiasing on anything but fonts 😛