Sigh. Not helpful. And also not accurate.
Some people use Photoshop for more than cropping forum avatars to 150x150.
Right now the CPU is the biggest thing. A good gpu can help to a point and ram can also be a limiting factor but you will see the biggest gains across the board with a better cpu. You won't see leaps and bounds between different i7 models, but just like with gaming, the intel lineup generally does better than AMD (by a pretty big margin in pretty much every test I've seen). Since you can't really benchmark cpus by FPS or a number like that, you have to rely on photo processing and filtering times of large images. This gap can be as big as 60 seconds if you are looking at previous generation cpu's vs current.
Not that I've looked into it, but logically a good GPU should improve the performance of all of the 3D tools and anything that re-draws the screen like zooming. Working with a large file on a computer with a bad GPU is a horrible experience. I remember a friend told me liquify and similar tools are heavy on the GPU as well. So if you're into retouching photos and have a beast of a camera then don't ignore the GPU.
As you know, the CPU should speed up mostly every process but I have no idea of how much. Perhaps Adobe benchmark their software to different hardware?
As far as I know, RAM is pretty much only useful for having a high number of history levels so how much you need it probably depends on how destructive you are when you work.
In all honesty, a 3570k along with a good GPGPU with a nice amount of RAM (scratch-disk on a RAMDisk will do wonders) will get you very far. Going with a 3770k instead might speed up processing slightly, but not sure if it's really worth it for PS. I'd rather get two storage drives and a fast SSD then.