[New Build] $400 for mobo/psu/ram/cpu

Hi, my brother asked me to build him a new computer for christmas, but I think I'm just going to give him most of my current computer parts and upgrade my computer.

My computer now is:

Case: Corsair C70
Mobo: AsRock 970 Extreme3
CPU: AMD FX-8120
Ram: Corsair XMS3 1333mhz 8GB (2x4GB)
GPU: Gigabyte Radeon HD 6850 1GB (factory overclocked at 820mhz)
PSU: Corsair CX500
Cooler: Antec Khuler 620

I'm going to give my brother pretty much everything minus the case, hard drives, and optical drive of course. I'm going to put all of it in my old Thermaltake V3 Black Edition case.

As for upgrading my current build, I already ordered the following:

GPU: MSI Radeon HD 7870 HAWK GhZ Edition ($189.99 after reabte)
Cooler: Antec Khuler 620 ($35 after rebate)

I believe the AMD FX-8120 is going to be on sale on boxing day for $109; Corsair CX500 for $30; AsRock 970 Extreme 3 for $60, and Corsair XMS3 8GB 1660Mhz for $30. Should I buy exactly these, or are there other options that would be better suited?

And for $109, I'm pretty much dead set on the 8120, unless the 8150 is going to be on sale for under $150. Either case, I'm getting one or the other (unless you all think there's a better cpu?); so it really boils down to the motherboard that I'm going to look at; preferably one with 2 pci-e 2.0 16x slots. NCIX has the Corsair GS700 on sale for $59.99; so I think I'm going to get that as well. As for the ram, I want to try and get 16GB (2x8GB) with at least 1600mhz and CL9-10 (if there is CL9 2x8GB ram available).
Finally, my price range for mobo, cpu, ram and psu is going to be around $400 max. Sorry if my post has been a little disorganized  

*Canadian retailers only please!