So this is my current plan for my new rig as of now.
Already picked up my new mouse since I literally wore out my current one with the 72hr contest.
Some things I'm not 100% sure on:
CPU: Do I really need an i7? Could I perhaps go for an i5 instead and maybe get to bump something up elsewhere with the savings? Is there going to be much of a dramatic difference to warrant the cost?
Motherboard: I want something easy to overclock with. My current MSI board has OC Genie built right into the card, I literally just press a button in and boot it up and it's overclocked. Not sure how this all works these days.
Monitor: I just want something with a low response rate and bigger than 22". Anything cheaper out there?
Storage: I am sitting on a Intel 120Gb x25-M SSD currently that I was going to pull out of my current machine, is it worth it to pick up something more current? Is there a big difference in performance? I'm seeing a few 240Gb SSD's sitting around the $80 price range. This something worth looking into for the extra room on my primary drive?
PSU: 750W overkill for this build?
Okay, so
CPU: In 80% of games you will hardly notice a major difference in performance between the i7-4790K and the i5-4690K, but in other more demanding applications (like Hammer) you might. If the Hammer compiler is good with multi-threading (I'm not sure if it is), you will especially have better compile times with the i7.
Motherboard: Like iiboharz said, most good motherboards today have some sort of automatic overclocking feature. But obviously, some are generally better/more stable than others. In this test (Swedish website), for example, 4 different popular Z97 motherboards were reviewed and compared against eachother. According to this review, the Asrock Fatali1y Z97 Killer had the "best" automatic overclocking feature, but the ASUS Z97-A had the "most advanced" automatic overclocking functions, and also the highest overall score in other categories. The MSI Z97 Gaming 5 had the "worst" automatic overclocking, and the Gigabyte Z97X Gaming 5 apparently automatically overclocks by itself without the user knowing (so I'd personally stay away from that particular model). I've also tried the automatic overclocking myself on my own ASUS P8Z77-V motherboard, and I think it works pretty well. Just make sure whatever automatic overclocking you use doesn't go too crazy on the voltage.
Monitor: Depending on the quality of your two old monitors and whether or not you want to use Nvidia Surround (which has a lot of requirements), I'd recommend either getting a monitor of similar quality to those ones if you want to save money (like you're proposing), or to get a much better one (in terms of response time and refresh rate) to put in the middle and use as the primary monitor. In the second case, you might even want to wait for G-Sync monitors to come down in prize (or fork out a lot of money to buy one now, like the ROG Swift) since that technology is pretty awesome, or even buy an AMD graphics card instead and wait for FreeSync (which may or may not be less expensive than G-Sync in most cases). To answer your question though, here's one: http://pcpartpicker.com/part/asus-monitor-vn247hp
Storage: As long as you have a secondary hard drive, your old SSD will do just fine if you manage your space correctly. If the only game you have on your SSD is TF2, and the rest of your games are on the hard drive, you should have plenty of space left. But if your hard drive is really slow at loading games, I guess you could add another SSD (which you would then use as your boot drive since it would probably be faster) so you can have faster load times.
PSU: No. It's also always nice to have some headroom as long as you don't have to pay too much extra for it.
I'd also like to add two things I said in an earlier post that I still think are important:
As for the memory [...] Just pick the cheapest kit you can find with CL9 or lower latency, 1.5V or lower voltage and 1600MHz or higher clock speed from a reputable manufacturer. (You may want at least 1866MHz with this budget.)
Anyway, the only other thing I have to point out is that I think the Supernova NEX and the Supernova G2 are not the same thing, and the Supernova G2 is the only one I've seen get excellent reviews.
Other than that, good luck with this awesome build!