Before posting a question like this it would be nice to know what kind of hardware you already have.
For these types of video settings, these are my personal recommendations.
Notes on the Mid-Range GPUs: These are perfectly capable of running most games on 1080p at Ultra with 60fps or higher. Skyrim is no exception in most cases even with ENB + 2K Textures
Mid-Range: (Skyrim)
nVidia: GTX 770, 970
AMD: R9 280X, R9 285
High-Range: (60fps Battlefield 4)
nVidia: GTX 980
AMD: 290X
An honorable mention is the GTX 780Ti, you could get 60fps on ultra with a little bit of overclock.
I didn't put in the GTX 960 for Skyrim, because it's memory bus seems to limit the GPU quite a bit, this seems to only appear on games that demand high resolution textures being loaded/swapped constantly during gameplay.
For Skyrim just make sure to check out the S.T.E.P guide and various forum threads on how to get the best performance/quality ratio.
If you have at least an Intel 2nd gen. Sandy Bridge i3/i5/i7. Or an AMD FX with 6 or 8 cores, you should be fine and the GPU's shouldn't bottleneck your CPU. I shouldn't forget to mention that AMD Phenom II six cores are still alive and kicking.