MoBo / CPU - I'd want a dual slot board so ya can upgrade to a 2nd GFX card some time in the future which will extend your system's life significantly .... a 570 might be enough for 90% of today's games but perhaps by this XMas, and certainly next, you'll be looking for a boost in frame rates and a 2nd GFX card will do that for ya .... much better option than having to build a new system just cause ya don't have that 2nd PCIE slot and 100 watts of PSU power.
PSU - A 650 watter is more than enough for this system, but not enough to ass a 2nd GFX card. Now would I power twin GFX cards off a TX series. Moving up to the Corsair HX850 would add $50 to ya system cost but the XFGX Black Edition 850 is every bit as good a PSU as Corsair's HX850 (both get same performance rating at jonnyguru.com) but only costs $10 more. If ya sure you'll never improve ya system w/ a second GFX card, then ya don't need an HAF-922 nor a 750 watter. Ya could save $71 w/ an Antec Illusion and a EA-650
Twin GFX Card Case / PSU Plan ($200)
$110 PSU - XFX Black Edition w/ $90 HAF 922 http://www.newegg.com/Product/Product.aspx?Item=N82E168... http://www.newegg.com/Product/Product.aspx?Item=N82E168...