at XS, they benched a Phenom 9850 against a Q6600, both at 3.4GHZ
the Q6600 got a higher CPU score in 3dmark06, but the Phenom system got a higher overall score.
It seems the Phenom is designed to work with the video card well.
There have also been reviewers (independently) say that the Phenom systems have a smoothness that's not there on Intel systems even if the fps might be behind.
I'm not going to debate that though.
If you do go for a Phenom system, I'd recommend looking at a DFI, Gigabyte or MSI 790FX board. They seem to be the better overclocking boards.