I did this build for a friend of mine. He had a $700 budget, but we ended up breaking that just a tiny bit. It came out to about $710 total. We already had the CD-ROM drive so we spent about $19 less than what this is listed as, but we still broke the budget regardless.
Anyways, this machine is primarily for gaming. We couldn't quite afford an unlocked 3570K, otherwise that would have been my primary choice. We got the 3470 for about $180 though, so it wasn't all that bad for an alternative. Since we ended up choosing a locked CPU, I decided the H77 chipset would compliment it best. The RAM was chosen simply to match the PCIe slots on the board - I like to match colors if possible. The Seagate HDD was the cheapest choice for the size.
I like the performance the Radeon 7870 XT can output, so naturally we decided to go with that for this build. The Zalman Z5 Plus case was a surprise. I was expecting it to be a pretty cheap and flimsy case, but it's actually quite nice and durable. The only con to that case is that the front USB header doesn't plug into the motherboard's header... it plugs into one of the mobo's rear 3.0 USB ports. I was so disappointed with that.
The PSU, despite being non modular, was very easy to work with actually. I found it pretty easy to do some good cable management with it. Very satisfied with that and the price it came at. The case was great for that. I should also mention that we got a 600 watt because we intend to CrossFire in the future.
Overall this was a great build to work with and once we got it up and running, the gaming performance was excellent. My friend and I are very happy with it.