MSI Z97 Gaming 5 question.

Have a look at Anandtech's detailed review here: http://www.anandtech.com/show/8582/msi-z97-gaming-5-motherboard-review-five-is-alive

Short answers:
OCing: Pretty good for manual OCing
Audio: Not sure - but unless you have analogue audiophile headphones it probably doesn't matter - any USB headset won't use the onboard audio, so it's irrelevant.
Two Red USB: "Gaming Device Port" -> MSI marketing BS... they're just USB ports with "3x more gold"
M.2: only disables SATA port if using a SATA SSD. It's only PCIe 2.0 x2, so definitely not worth putting a premium SSD like the 950 Pro in there. Not sure above NVMe boot support either. If you want to go 950 Pro (which I'd question - it's very rarely worth the money unless you have some very particular workloads) you should be looking at a Skylake (6xxx) CPU and Z170 motherboard. They have native NVMe and most have proper PCIe 3 x 4 M.2 slots which will actually allow a 950 Pro to stretch its legs (again - if you have the workload, which you probably don't).

It seems like a solid motherboard. There are plenty of other decent options at that price point though, including proper M.2 slots if that is actually a priority for you (ASRock Z97 Extreme 4 for example).

Are you really basing you purchasing decisions off a future 950 Pro? Are you sure you have some specialised workloads that will actually be able to push that drive hard enough?

/rant/
If you don't have a genuinely intensive IO workload it's a bit like purchasing something like THIS to tow a standard box trailer for a family camping holiday. Sure if you load up the 950 Pro with a server grade, massively intensive IO workload then it will show you what it's made of. Run a script to update 100,000 addresses in a database, or boot 8 virtual machines simultaneously and the 950 Pro will destroy any standard SATA SSD. There's no question it's a powerful drive. But the reality is that even an enthusiast PC user just never generates the kind of intensive workloads that allow a drive like that to separate itself from the mainstream SSDs on the market. What do you do with the PC? Boot it, open a program or two (or even five) at once, copy files over the network, install a new program once in a while... that's child's play for any SSD, let alone the 950 Pro.

Anyway, it's your money, obviously you can spend it where you like, but unless you have a particular use-case there are far, far better ways to spend your hard earned cash....
/endrant/

OK, now that rant is out of the way, if you're going all-in on M.2 storage remember that a PCIe M.2 slot is just PCie lanes, so you can get cheap, dumb PCIe cards with an M.2 slot. It's just routing PCIe pins to the correct M.2 pins, so they work seamlessly. Just be sure your BIOS supports NVMe booting if you're going with an NVMe M.2 drive (like the 950 pro).
You can go all-out on X99 and 2x Ultra M.2 slots, but it's $500+ worth of motherboard, + new CPU + new RAM: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157535&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-PCPartPicker,%20LLC-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=3938566&SID=
Terrible idea IMHO, but it's an option. (You realise your 4770K won't go in an X99 mobo don't you?)

In terms of wifi: is it just for Internet, or will you be transferring files over the network too (home NAS)? If it's just internet AND you *don't* have an ultra fast cable connection AND the router is pretty close, then it doesn't really matter as any half decent wifi adapter should do the trick. If you need more performance (for local file transfer or >100mbps internet), or you need better than basic range, then you should look at a PCIe card that has multiple external antennas.

Hope that's helpful.

OK, fair enough. With the latest BIOS, the Z97 Extreme 6 does support NVMe booting, so there's no reason really not to get your high SSD now and put it in the x4 slot if that's a priority for you. The remaining x8 lanes really are plenty for a GPU.

In terms of RAM, you don't need to spend $70. Here's a sorted PCPartpicker list for you: http://pcpartpicker.com/products/memory/#Z=16384002&s=301866,302133,302400,302500,302600,302666,302800&sort=a10&page=1

I'd get the Muskin 2400Mhz kit for $60 myself, but the yellow may not be to your taste. The G.SKill 2400Mhz options (Ares or Ripjaws) are reasonably priced too. I don't think it really matters TBH.