4670 is itself a superior CPU. If your needs are based on gaming, CPU's high per core performance is 100% mandatory. Taking 4690 into the account, it's single-core performance is very similar to 4670 and hence it is negligible. If you strictly fix your mind for overclocking, I would then recommend K version yet there will be no much difference between 4670 and 4670K. As per the price/performance ratio, 4670 bags first place and secures its position. From the starters to experts, 4670 is considered a flawless gaming CPU, which is also a bang for the buck.
As a conclusion, you can save your money on your processor by affording 4670(Non-K version and strictly gaming). If you want to workaround with photoshop, aftereffects and other multimedia things, I would then recommend i7 which comes with Hyper-Threading freature. Should the budget is skinny, then go with 4690 to have the advantages in different areas of multimedia including the gaming.