Wow, a lot of people on here seem to be not sure what ultra on modern games will require. You will not need an i7 with a 770. If you get an i5 4670 or an 8 core amd FX you will be fine running modern games and games for the next 5 or so years on ultra settings. For the graphics card, a 660 can run modern games on ultra settings, mine does. For extra future proofing though, a 760 would be a good budget conscious choice that would run games on ultra for the next 2 to 2.5 years. A 770 would last you even longer probably about 3 to 3.5 years. Keep in mind though, that when you hit that 2 year mark with a 760, that simply means that games that come out at that point may require you to do a mix of ultra and high settings, it won't be like 2 years and then you have to play on low settings. By the time a 770 would not be doing good on ultra, it will have endured alot of use and will need to be replaced anyway just because it is tired and worn out. So anything beyond a 770 is just for bragging rights.
A lot of times on these forums, people like to think that if you are not getting over 70fps on ultra, it is time to upgrade. Truth is, you are not going to notice a difference between a constant 45fps and a constant 60fps. Anyone who says there eyes can easily detect the difference needs to doubted on their opinions.