The Phenom II is a capable gaming CPU and can keep pace with Sandy Bridge in most gaming configurations at modest resolutions with a modest GPU.
That said, with the 7000 series it might start to look long in the tooth. It won't be an ideal match, but my guess for what it's worth is that it won't be too much of a bottleneck.
The thing is, basing buying decisions on the PR smoke and mirrors that AMD, intel, and nVidia spew out through their marketing departments is a bad idea IMO. We don't know what the Radeon 7000 is going to turn out to be, if anything. At the very least, it's still going to be a DX11 part and it's highly doubtful that it will have a GPGPU platform to go with it or any significant new features.
If you want a fast DX11 part that's energy efficient, my bet is that the 7000 cards will be nice, but if you want to game now, there are cards on the market for a good price if you look around.