i5s are really the best gaming CPUs worth buying at stock and since one fits in your budget, I recommend one. I recommended one that isn't a K edition because you say that you don't want to overclock.
Pretty much any motherboard will do for you since you don't want to overclock.
Since you're not overclocking, you could skip the CPU cooler, but it has an $18 off combo deal that I wouldn't recommend skipping. For $12, you get a cooler that is quieter and better than the stock cooler. It's not even a 2% increase in budget, so why not.
Any 8GB memory kit that is at least DDR3-1600 10-10-10-30 is pretty much ideal, so Ill usually recommend the cheapest such kit or better kit when they're the same price or cheaper. Going beyond even about DDR3-1066 7-7-7-21 or thereabouts tends to not have a significant performance impact, so it's simply not worth spending more on expensive memory.
Unless you think that a 1TB hard drive is not enough capacity for you, I'll recommend one and this Caviar Black is among the fastest and most reliable as well as the cheapest since this model is on sale (it's usually much more expensive).
Samsung 830 SSDs are generally among the most reliable and also among the fastest. They also tend to use almost zero power and this one is on sale.
This 7870 is one of the cheapest as well as one of the fastest and is an otherwise good card. No Nvidia card in its price range can touch it in most gaming situations.
The HAF 912 is among the best cheap cases and is plenty for such a build.
This is a fairly reliable PSU from one of the best PSU companies, Antec, has more than enough power delivery, is fairly efficient, and is modular.
Pretty much the cheapest DVD writer is what I'd recommend and this is it last I checked.
Windows 7 Home Premium x64 should suffice for your operating system needs so long as you don't plan on using more than 16GB of RAM. 16GB is no better than 8GB for most uses (including gaming) and won't be any time soon, so I won't recommend it for you unless your editing includes very intensive video/picture editing and you know that you'll need 16GB for it. If you want 16GB, then I'd recommend a Windows 7 x64 Pro instead of Home Premium just in case you ever want to upgrade your RAM capacity beyond 16GB before replacing this computer or upgrading its OS.
I think for the extra ~ 20$ you'd spend overclocking would be worth it. just my 2 cents.
EDIT: Definately would be worth it. + ~20 dollars (- like 40 if you have a microcenter) for the 3570k, then you have that sweet deal on the cooler, I think the extra 20 bucks would be 100% worth it. SIDE NOTE: I always get excited when I put together a great build for a great cost for someone, then I remember "Oh, darnaduck, I they an OS!"
so then I have to limit the money I've got from them for a freaking OS. WHY ISN'T W7 40 BUCKS NOW THAT 18 S OUT? ;_; DAMN THEE MICROSOFT.
Yeah, I did post before your edit, but that doesn't really make a difference IMO. Basic gist is that overclocking isn't much more expensive at all, but can make a significant to huge performance difference.
Kay. I wasn't sure what the price difference was between the 3450 and the 3570 (Non k) (why would you even..?) so i had to research it to make sure what I was saying wasn't off by like 40 bucks. hah.
Why would I go with the 3450 instead of the 3570? They're too close for stock performance to make a noticeable difference, so there's no reason to spend even the fairly small price difference between them unless you pass the 3570 up for the 3570K and some serious overclocking to make a performance gain worth paying for.