So, I have a feeling I'm answering my own question here, but I just wanted to confirm that I'm thinking the right away before throwing away a few hundred dollars. I think I have a pretty great setup on my desktop PC for playing Skyrim, and when I had it built, I had no complaints since it could smoothly run the game on Ultra. However, I've been testing out ENBs and looking at some newer games due to come out this fall, and they have me concerned that my specs aren't what they could be. So basically, all I'm asking is if you had to upgrade one thing on my current rig, what would it be, and would it make running an ENB less of a cost to FPS? On the same note, would upgrading the same thing give me the benefit of being able to play more current or future games at full quality settings? I'd hate to upgrade just for the sake of using a mod and find out a couple months down the road that the upgrade wasn't good enough. My current specs are below. Thanks for any suggestions I receive.

OS: Windows 7 Home Premium (x64)
Processor: Intel® Core™ i7-2600 CPU @ 3.40GHz, 3401 Mhz, 4 Cores, 8 Logical Processors
Graphics: NVIDIA GeForce GTX 550 Ti
Sound: Realtek High Definition Audio
Physical Memory (RAM): 16.0 GB
Virtual Memory: 32.0 GB

And for those wondering, my game runs around 60 without an ENB, but it drops down to 25-35 when using SSAO, depth of field, the new shadows, and the skylighting.

Graphics card. No question about it.

If I upgrade to a NVIDIA 670, would I need to upgrade anything else for it to run at its full potential? Is there a particular version of it that I would need for my build?