How do I chose which Intel chip to get?

I bet it wouldnt be worth the upgrade since you realistically would buy a 4690k for $220 if you find it on sale, Then you would need to get a new mobo and while Asus are great mobos they arent the cheapest brand so add on another like $150 and I'm assuming you already have a good cpu cooler but if not add on another $30. Thats not worth the performance increase.

The rule of thumb is that you dont upgrade cpus that arent atleast 2 Tiers ahead of your current one on this chart: http://www.tomshardware.com/reviews/gaming-cpu-review-overclock,3106-5.html

Which there currently arent any

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor ($224.99 @ NCIX US)
Motherboard: Asus Z97-A ATX LGA1150 Motherboard ($144.99 @ Amazon)
Total: $369.98
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-08-24 02:20 EDT-0400

This will be best for you OP

The performance increase would not be worth the price.

Tbh, from what I hear Watch Dogs and AC get some framerate drops for pretty much everyone sometimes. It's something about the Anvil Engine (and the bits of the Anvil Engine used in Watch Dogs). I far prefer Ubi's Dunia 2 Engine, not really sure why they used so much of the Anvil Engine in Watchdogs because it clearly butchered the performance.

That said, Assassin's Creed at least isn't optimized for many cores, so it may still benefit significantly from an i5.

Clock for clock, haswell i5's and i7's can deliver up to ~75% higher execution performance to real-time workloads compared to piledriver FX chips. That can mean substantial differences in minimum FPS. Especially noteworthy and meaningful in conditions that are GPU heavy with high FPS goals in compute intensive games (multiplayer).

IMO Toms gaming hierarchy chart has some pretty serious errors developing. I hadn't seen it in while till participating in this thread. I'm not sure whose in charge of that chart but my research on the issue and those "positions" on the chart don't make any sense to me at all for many of the chips listed....

I could point out many obvious errors (I see CPUs listed 2 tiers apart that I know from research and testing to have very similar performance in real-time workloads), but lets not worry about that for now. Whether or not a CPU is "enough tiers" of difference on Toms chart probably shouldn't matter as the chart is fundamentally flawed for its intended purposes anyway. Maybe I can help them sort that mess out sometime. What should matter here, is whether or not your workloads are apt to take advantage of that potential ~75% advantage in available execution performance in real-time/gaming workloads.

If you don't mind spending a couple hundred more I would suggest a MAXIMUS VII RANGER with a 4790k...

In compute intensive games it can be a lot more than 10%. The execution resources available in a haswell core are significantly "wider" than a PD core. (approximately double). Real-time workloads run much better on the big-core intra-core parallelism level. Users who make the switch from many-core to big-core for compute intensive games consistently report significant changes in game-play smoothness etc. The only way to "hide" or shrink the difference to ~10% or less would be if the render workload were adjusted to solidly plant the bottleneck on the GPU configuration at all times at a relatively low FPS (~30). If your idea of smooth game-play is 30FPS, then yes, a switch to haswell may have very little effect. If you're like most competitive gamers, who notice FPS minimums when they drop below ~50-60FPS, then you will likely benefit from a switch to haswell by significant margins. If you work for the AMD marketing and deception department, then you would find a way to demonstrate that the FX chips perform similarly to the competition. Easy: hide the difference under the rug of a GPU bottleneck.

When the news media takes White House propaganda/talking points and turns it into news, I am ashamed of our media. When freelance forum participants take the bullet points of the hardware marketing departments and basically share them as fact without question, I am ashamed to wear the badge of "geek."

Clock for clock, haswell can indeed produce up to ~75% higher minimum FPS in many games, though in some cases, it can be even higher than this due to the way draw calls can be slacked off in some game engines to preserve a cohesive timeline. This depends on how the game engine functions are tied together to the timeline. The compute overhead available above and beyond the minimum required to keep up with the timeline of events/AI etc, can, in some game engines, winds up having a dramatic effect on FPS. I've observed this behavior in testing. Stock clocked a CPU might cause FPS minimums to dip as low as say 20FPS, but then a mild overclock of just 10-20% could improve those minimum FPS to 30-40FPS, because that 10-20% of compute overhead actually nearly doubles the available headroom for draw calls. This may seem counter-intuitive, but many games do wind up responding this way to changes in compute performance. The substantially wider haswell instruction engine offers a much larger piece of compute overhead pie for draw calls, and thus, solves those nasty FPS minimums and glitches in MANY games.