If they make a power-efficient (I'm thinking 45W) APU that can put out 80-120mhash/s with 400-600 Radeon 7xxx series shaders, CPU mining will be worth it.
Granted it's not much in daily BTC, but it will pay to keep the processor mining, unlike now.
Agreed. For new mining rigs, it might make sense once they have some 3-4-5 pci-e slot boards. You'd get the same GPU production with a bonus 50-80mhs from your cpu.