What ketchup said, but I'll make a few comments/additions:
Motherboard: That looks pretty nice, and it's listed on the osx86 project compatibility page.
CPU: Whee fast.
CPU cooler: Don't use Intel's stock one, it sucks. I have the unfinished version of this guy, and it's awesome (black chrome plus LEDs make it even awesomer): http://www.newegg.com/Product/Product.aspx?Item=N82E16835233029
RAM: Newegg had a 16gb DDR3 kit on sale for $65 not too long ago, so that would be something to look for on Black Friday.
SSD: Sandforce is the fastest, but there are reports of some reliability issues. I have an OCZ Vertex 2 in my Mac Mini that has given me zero issues, so YMMV, but it doesn't matter as long as you have some form of a backup solution (which you should anyway). Another option is the Crucial M4 (Marvell-based, not Sandforce): http://www.newegg.com/Product/Product.aspx?Item=20-148-442
HDD: Wait if you can, though last week Best Buy had the WD Green 2tb on sale for $80. Keep a look out for non-ridiculous prices.
Graphics card: Yep, that's fine, unless you prefer AMD. If so, I can make a recommendation.
PSU: Corsair PSUs have Seasonic internals as well. Look for a single rail because it makes it easier (you don't have to worry about balancing the load across rails). You can't go wrong by picking a power supply on the silentpcreview.com recommended PSU list
Case: Antec cases are nice. I was actually incredibly surprised at how nice the Antec 200 is. (My dad just bought one from Newegg for $25 after rebate) I was expecting it to be a budget-quality case, but it's not. I have an Antec 900, which is also nice. Cooler Master also makes good cases. I'd look at the various Cooler Master and Antec cases and find one that you like the look of.
Mouse/Keyboard: Depends if you're picky or not. If you're not, a $20 Logitech mouse/keyboard combo will be fine. If you are, I've read that the Rosewill mechanical switch keyboards are nice. There's a video on the product page that describes the differences between the color of switches: http://www.newegg.com/Product/Product.aspx?Item=N82E16823201040
Another excellent option would be the older IBM Model M. In general, the higher-quality keyboards have mechanical switches, so that's something to look for.
I have two of this mouse, and I like it a lot. No-lag wireless plus a ludicrously-small receiver and fantastic battery life (i.e. I've had mine for a few months and haven't needed to replace the batteries yet): http://www.newegg.com/Product/Product.aspx?Item=N82E16826104382
Yep, think that's about it.