Would you upgrade if you were me?

Okay, so I'm currently rocking an AMD athlon II x3 455 at 3.3ghz with the 4th core unlocked (phenom II x4 b55) on a Biostar 880g+. This combo was originally put together two years ago for web surfing and the building experience only. This summer I decided to sell my consoles and make the transition to PC gaming exclusively. I bought a Gigabyte Windforce rev.2 GTX 760 and it's a fantastic card and I can play all the games I own. This includes demanding titles such as Crysis 3, Far Cry 3, BF3, Bioshock Infinite, Witcher 2, and Metro 2033/Last Light. However, I have noticed when running MSI afterburner, that in all these games my GPU never runs at 99%. For example, in BF3 it runs anywhere from 50% to 80%. So I definitely have a pretty significant CPU bottleneck.

I've been researching a CPU and motherboard upgrade that won't bottleneck my 760, but that will give me the ability to upgrade to future GPU's years from now without worrying about a bottleneck. Therefore, I plan on going with a i5 3570k, xeon e3 1230v2, or fx8350 this fall. However, I don't feel that I really need to upgrade, that I could hang on for a year or so more with my athlon and wait for the next generation of Steamroller or Broadwell parts. I CAN play all the games I own right now at highish settings so I wouldn't call an upgrade necessary but it would definitely help me bump up settings, it would get rid of the frame drops that I'm experiencing and it would allow my GPU to run at it's full potential. 

Anyways, if you were me.... Would you upgrade? Or would you just stop worrying about it and play the latest games until they become unplayable?

I would certainly look to upgrade. It really depends what you're going to be happy with. Only you can decide if you're prepared to wait.

If you want until next year, there will always be another platform announcement, or something to follow. I don't think you will be disappointed with anything that can be bought at this time.

if i were you i'd do ANYTHING to improve my life (your life) one iota.

Depends how much you're willing to spend on said upgrade. If you have the funds now, it wouldn't be a bad idea to upgrade as I don't think either broadwell or steamroller are going to bring any crazy advancements to the table. Also, why upgrade to ivy bridge? haswell costs pretty much the same, is newer tech and performs a little better. 

But anyways yeah, you could go i5-4670k or 8350 right now and both those would last you many years easily. 

Or wait for broadwell/steamroller and see how they perform when released. The choice is yours. As you said, your system is still performing adequately.  

Reason I'm going for Ivy bridge is it would be about $40 cheaper considering the CPU and the mobo I would get vs. the z87 mobo I would get if I went haswell.

I wouldn't upgrade the CPU yet, there is no or close to no bottlenecking in that build. You may not be able to max out crysis 3/metro because these games are CPU intensive but in most games your processor will be just fine because at 1080p all the hard work is done by the graphics card.

So every thing has just changed. My roommate has decided he wants to upgrade his motherboard. He wants to sell me an Asrock 970 extreme 3 for $20. This is basically free. At first I was thinking I could maybe try and sell the board and use the profit to help purchase my Intel CPU and board. However, what if I just threw an FX 8320 in there?

I'd prefer going Intel, but for $170 I could have an fx8320 and a motherboard versus the $350ish it would cost me for z87 setup. I'm very tempted to take his offer.

no bottle neck there.

If I was in your position and could get a mobo and 8320 for only $170 I would take his offer.

I would be skeptical about putting an 8 core in a cheap 970 board. You might want something a little bit lower power like a 6300 or 6350. Just food for thought.

I would upgrade and either go am3+ with a 6300 or 8350 if you want a really good upgrade.

I was worried about that as well, but after some research I found that people matching this motherboard with an fx8350 were able to run it fine at stock speeds without throttling and some were even able to squeeze out a tiny over clock. I wouldn't really be interested in over clocking. In fact, I might try and under-volt the fx8320.