Assuming you mean for gaming i do a i5 3570k and either the 7850 or gtx 660/660ti. The i5 3570k is a much better processor than anything AMD has out right now. GPU wise either of those choices would be suitable.
At lower resolution the 660 Ti might pull ahead as it has an insanely over-speced texel rate (due to being a defected GTX 670 GPU, they have other bottlenecks internally).
The GTX660 Ti has much less 'spikey' gameplay though, as a result of having 112 texel units vs the Radeon's 64.
- Personally I'd lean towards the GTX660 Ti as I don't trust the first iteration of the 'GCN' Radeon HD's from AMD/ATI.