Couple of quick comments:
1: Do you intend to overclock? If this is for gaming alone, then the intelligent answer is: No im leaving it at bone stock clocks/voltages/buss speeds. If this is the case, take it back to a i54670 drop the K, and scratch the aftermarket cooler. Nothing, I repeat, NOTHING, in the gaming world that I've encountered, can choke down my 4670. Nothing. You don't need it. If your answer was yes, then the following advice will also fall on deaf ears.
2: RAM. again, if this is gaming we're talking, you can't use all 16 gigs, its just not possible. Running every game that will run, which is over 80, and all the programs I can find on my HDDs, and my ram usage sits at 90%. Everything is laggy as hell, granted, but thats my CPU choking down, and with good reason. As I posted in another, similar thread, the biggest trap for a new guy is hte frequencies. People wax on about high frequencies when their CAS latency is just too high, like 12. For gaming, I suggest 8 gigs of Gskill ram. Be it 1333 mhz or 2866, thats your perrogitive. What you want to be looking at first and foremost is CAS latency, and CAS9 is a good one to shoot for. Its not woefully expensive and is very quick. 1600 mhz is fine, I doubt you would see much, if any performance increase by punching it out to 2400 for example. High load, high IOPS scenarios like gaming and server hosting is where CAS latency and frequency have to be much higher on your list than capacity. On WIN 7 I'd be happy going wiht a tripple channel, CAS9 2133mhz set of RAM. Thats a very quick setup and will wipe the floor with your current 16 gig setup thanks to the higher frequency. I'm rambling now, but its an area that so many people get swindled in. Bottom line: Don't go over 8 gigs (or under with windows 8), get CAS9 and 1600 upwards FOR GAMING.
The 780: I know it feels great to be able to say you have the fastest GPU on the planet (and it is by a mile), but will you really spend an extra $300 just for bragging rights? Really? Let me put it to you this way: My EVGA GTX 770 SC edition with the twin fan cooler, is currently running in a PCI-E 2.0 lane, because my mobo failed and had to be sent away. I also had to roll back my CPU. This brings my rig to: Core i5 760 bone stock, Gskill 8 gig dual channel DDR3 1600 CAS9, GTX770 in PCI-E 2.0 and you know what? BF4 absolutely maxed out @ 1920x1080, never gets below 40 FPS. So if you still think you need a 780, you should think about throwing some of your obviously limitless funds my way once in a while.
Be wary of hte NZXT phantoms, I've had 4 fail on me. Well on customers who brought back their computers asking me WTF their hardware had just overheated 3 times in a row. The answer? All four fan controllers had shorted, meaning meltdown. Had to do absolute battle with NZXT to have the money for alll the destroyed hardware refunded on all four occasions, vowed never to sell one again. If I wasn't in australia where consumer law is heavily enforced, I doubt I would have gotten any of it back.
other than that, good job. Mind what I've said and have fun! Keep all receipts, take pictures of all the build process, post and back them up for awesomeness and insurance purposes respectively. Good luck.
EDIT: Forgot to mention that I strongly recommend a Kingston for hte SSD. Very quick, not too expensive and nice and solid. I've used 8 in various builds and received nothing but praise. I have 5 internal HDDs and only use my C drive for some programs, windows and save games so I went with a 60 with is enough for me. I would suggest a 120/60 SSD for your windows drive and getting a 3 tb barraccuda or other brand equivilent (seagate would be my most intense suggestion) for all your games, C Drive backups etc. That way you don't loose everything when you reformat.
Also my apologies for the RAM comment about only for gaming, I didn't read your post properly and missed the "dabbling in video editing and photoshop" part, my bad. But what I suggested will still be ample for that aswell, just thought I'd throw that out there.