My top picks, in descending order of price:
i7 7700K
i7 7700
Ryzen 5 1600
i5 7500
Ryzen 5 1500X
My opinion, the best deals are the 7700 (non-K) and 1600. The 7700K allows you to overclock but must be paired with a more expensive motherboard and needs an aftermarket cooler, which drives up cost a lot. It's only a good choice if you need the absolute best performance. The i7 7700 generally beats the R5 1600 in games but is more expensive, and falls behind in other tasks because the R5 has more cores/threads. An i5 7500 or R5 1500X are both fair choices for a bit cheaper, but don't seem to offer the same value as the 1600 or 7700 to me.