If money is absolutely no object, and unlocked i7 is the best as you get overclocking and hyperthreading, which a few newer titles do benefit from to an extent. The 4790k would be better than the 4770k because the 4790k tends to overclock better and doesn't run into the thermal wall quite as quickly.
An unlocked i5 would be in second place, and for most games it would offer just about the same performance as an unlocked i7 when run at the same clockspeed. There are a few newer titles that do show some benefit to the i7's hyperthreading, but you would also need a really high end GPU for the difference to be apparent, so it's not worth getting an i7 if you have to make major cuts to your GPU budget to fit an i7 into your budget.
If you're looking to overclock a Haswell chip, you'll need a Z97 motherboard. Beyond that, which one to get will depend more on what kind of features you want or need and how much SATA or USB connectivity you want.