Re: Overclocking, read this review of the Haswell architecture:
http://www.tomshardware.co.uk/core-i7-4770k-haswell-review,review-32699-10.html
Haswell isn't doing very much that Sandy/Ivy bridge wasn't already, and the likely reason for that discount is that enthusiasts who are most likely to overclock K series CPUs aren't very interested in the Haswell CPUs because Haswell OCs differently from Ivy/Sandy Bridge. I don't understand it fully, so I won't attempt to explain, but that article should give you an idea.
If you were to go with an Ivy Bridge CPU, you would be using an LGA1155 socket, which means you would never be able to upgrade; Intel is only making new CPUs for the LGA1150 socket now. So there is a compelling reason to get a Haswell CPU. And since the K series is within $15 of the cheapest model currently available in that lineup, go for it. The only cheaper processor that would be worth it might be a Haswell i3, which has not yet been released.
To see a detailed explanation of how Adobe programs interact with different hardware configurations, read this document:
http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/products/creativesuite/production/cs6/pdfs/adobe-hardware-performance-whitepaper.pdf
Depending on the amount of editing your dad does, you might consider buying 2x4GB of ram and see if your Dad is limited by that amount before purchasing the next two sticks or ask your Dad to shell out $50 for the two additional sticks =) RAM is very easy to install once you've made your computer as long as you don't have an enormous aftermarket cooler that blocks it. There is a right and wrong way to install only two DIMMs when you have 4 DIMM sockets, so read your motherboard's manual carefully for this information.
My goodness. An upgrade to a GTX 660/670 from integrated graphics? You're going to enjoy that.
Under heavy loads, do the integrated AMD HD 4200 graphics draw on the 6 GB of RAM I have? If so, then I think that will be resolved with a discrete graphics card, which will have its own 2 or 3 GB of VRAM, enabling it to stop pestering my real memory.
I think you are correct about this.
But back to the photo and video editing, would the 16 GB be worth it in that regard? If you don't think so, I can save about $50 there and put that toward a 670 or 770 as you recommended.
That is definitely money better spent on your build. If your Dad is editing video in Adobe Premiere Pro, there is a workaround that allows you to enable GPU acceleration with any Nvidea GPU that has CUDA cores. Whichever one you get may already be on the list. My 560 Ti is not on the "approved list" but it accelerates rendering like a beast after the workaround.
I guess I agree with you on the PSU, too. I will look into 750 Watt supplies. Is that as low as I should go, or would I still be safe to go with a 600 W or 650 W, for example?
I think you could go lower than 750W. There's a bunch of hoopla about how PSU wattages are calculated. You don't have to worry about this if you get a reputable brand like Seasonic. Use this calculator for more info:
http://www.extreme.outervision.com/PSUEngine
DisplayPort compatibility - doesn't matter. Your monitor will be plugged into the displayport/hdmi/dvi port on your GPU anyway.
USB BIOS Flashback - are you sure you would need this? I've never had to flash my BIOS. There's not much to do in BIOS that can't be accomplished in the UEFI, which was invented to replace BIOS. When I need to change the overclock on my processor, change the storage mode on an SSD, configure the boot order, look at fan RPM, I can do it very easily from the UEFI. Read about it here:
https://en.wikipedia.org/wiki/Extensible_Firmware_Interface
Also, the Asrock is an H87, not Z87. Does this have major consequences? Doesn't it restrict overclocking?
Yes you cannot overclock the CPU with an Hxx chipset. You can overclock the GPU with an Hxx, though. Try this Z87: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157372. It is in the same line as the Z68 Extreme3 which I've used for a stable overclock on my i5 for 2.5 years now. You could even go cheaper within the ASRock lineup.
In comparison to the ASUS Z87-PRO I don't see any meaningful differences between the two models, except that the more expensive one will look prettier in a case with a window until it is covered up by an aftermarket CPU cooler =)
The important things to look for in a motherboard is
1) Does it have a PCIe 3.0 x16 slot? (the answer is yes for every Z87 chipset model)
2) Does it have enough USB3.0/2.0 ports for your devices (I'm thinking the answer is yes for every model; each also comes with headers that attach to the USB ports on the case you buy.)
3) Does it have UEFI BIOS (yes to all)
4) Does it have enough 6Gb/s SATA ports for all of the SSDs you're going to buy? (Yes, they all come with 6!!!! Crazy, right?) Also HDDs cannot saturate a 6Gb/s connection, so that's a moot point.
5) Does it have the proper rear panel ports for all of your peripherals? I can't answer that one for you.
Everything outside of that is pretty much just marketing (though I would love for another Tom's Hardware community member to educate me on this if I'm wrong) if you're a gamer.
Check out this
product comparison.
On the topic of GPUs, can you give me some basic information about the differences in GPUs, their clock speeds, VRAM, and their respective models? (Preferably just on Nvidia; I'm not really interested in AMD.) I've looked at ASUS' 660 TI OC (3 GB VRAM), and compared to many other cards on pcpartpicker.com, it seems to have superior ratings and reviews. Are the performance increases on a 770 worth the leap in cost?
I just look at benchmarks. It gets very complicated when you talk hardware in a GPU because the architecture changes so much between series. For instance, the GTX 660 has 1344 CUDA cores whereas the GTX 560 has 336. Seems like a huge difference, right? It isn't; the architecture drastically changed between the two series. In the 660 Kepler architecture, they eliminated the 2nd (shader) clock which required the use of a unified clock, which means they needed way more CUDA cores to achieve the same performance.
Likewise the core clock for my 560 Ti is 950MHz whereas the core clock for the 680 is 1084MHz, so you would think they would have comparable performance, right? Not even close. It is best to use benchmarks for the type of games and resolutions you like to play to judge differences in models.
Also you should definitely consider the AMD 7970. It is perhaps the best value on the high-end side of the market right now.
Storage... Is a 120 GB drive enough to store my OS and application data? I found a Kingston that's 120 GB, and it only costs $85. Would you recommend the Samsung 840 series over this?
Yes get the Samsung 840. Samsung is unique among SSD makers because they actually manufacture every individual part of their SSD whereas many SSD manufacturers purchase their NAND chips or whatever from multiple suppliers. So Samsung has much better reliability and performance. The other aspect you should look into is in the SSD controller. Don't get an SSD with a Sandforce controller because it relies on compression to achieve its fast read/write speeds.
128GB is plenty. After installing my OS, I had 80GB free. After installing CS6 and a bunch of games, I have 30GB free.