The 2600K demolishes the 8150, but it's a 2nd gen processor and the successor (3770K) is only some $20 more, so it makes more sense to get the 3770K.
Now, as to whether you will actually need the Hyper-Threading, you will only take advantage of it if you're running a decent amount of multi-threaded programs. For your usage, the i5-3570K is a more cost-effective option. Here's what I'd recommend:
Core i5-3570K: $215
Corsair A50: $30
ASRock Z77 Extreme4: $130
Sapphire Radeon HD 7970 OC: $400
Corsair Vengeance 8GB (2x4GB) DDR3-1600: $39
Samsung 830 128GB: $99
Seagate Barracuda 1TB: $82
Seasonic X650 Gold: $100 with code
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ASUS 24X DVD Burner: $20
Windows 7 Home Premium 64-bit OEM: $91
Dell UltraSharp U2412M 24": $269 with code
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Total: $1557.
The Corsair A50 I'd recommend over the CM Hyper 212+ because while it's a bit bigger it does give you somewhat lower temperatures. Its price is the same.
The Radeon HD 7970 over the GTX 670 because you mentioned overclocking. HD 7970 OC=GTX 680 OC. You get a card with heaps of memory bandwidth, which is becoming increasingly important in games. You also get a card that responds better to overclocking: not only does it overclock a higher percentage, but you gain more from it. The downside is higher power consumption, but that is somewhat offset by the fact the Core i5 uses so little.
The Samsung RAM is great and all, don't get me wrong, but the fact is you'll be lucky if you gain even 1% in performance on Ivy Bridge for going from 1600 to 2133. Ivy Bridge has plenty of memory bandwidth at its disposal, hence why higher memory speeds don't have any reflection in the real world but rather on synthetic programs.
The Barracuda over the Caviar Black because the Caviar Black is overpriced and simply rides on its brand recognition to sell. Not only is it slower than the Barracuda, but it consumes more power as well. The new Barracuda is the only Hard Drive able to achieve 200MB/s sequential reads; the Black in comparison gets around 120MB/s.
For $10 more you're getting much more power supply. At $100, the Seasonic X650 is a steal. It has higher quality components than the TX650 V2 like a Sanyo Denki fan, 80+ Gold instead of 80+ Bronze efficiency, and other features like running fan-less at low load and a fully modular interface. You also get 4x PCIe connectors instead of the 2x you get with the Corsair. And yes, this will run two HD 7970s in CrossFire.
Finally, the monitor is one of the most important things in your computer. It's what you'll be seeing day-to-day. The Dell U2412M is on sale at the same price as the U2312M, and for that you get some significant upgrades: (1) you get a display that is much taller due to the 16:10 aspect ratio and (2) you get a higher 1920x1200 resolution to go along with it.
Not only is this build better, but it's cheaper as well.
