Well, "best" will vary from one person to another, and also depends on the games you will be playing. MMO games tend to be more cpu demanding so you may notice the difference of using a cpu with more core or higher speeds while on fps's like COD the difference may be so small you don't see any differences. Then there are the people that are always looking for the best value processors and call those the best. With the way that most of these cpu's will overclock, I wouldn't really bother getting a higher speed cpu based on the same architectures. For example, the i7-2600k vs the i7-2700k, you could easily overclock the 2600k past the 2700k and they will most likely have the same upper limit with overclocking. All that being said, normally I would recommend a 3770k but can't seem to find any on the egg.

4930k would be the best followed by the 3770k

I vote 3770K.  I still have it in my other rig.  Runs at 4.2 with no voltage tweak.  Great processor

jonathancoleevgaI considering upgrading my rig and going for an ivy processor, as my mobo is compatible with both sandy and ivy. what's the best ivy cpu for mainly maxed out gaming on 1080?

I suppose the answer is "the fastest one you can afford" ... lol.  Seriously, the i5-3570K was supposed to be great, and would likely be sufficient.  The i7-3770K might be worth looking at for HyperThreading and the extra cache - I know a lot of games don't currently use multiple cores well, but it might change in the future, although there are some exceptions currently, e.g. Metro.