New AMD + old 945 + 6670 with $3-500 to spend

Hello
I am getting the itch again! Time for an upgrade.

I have a new LG 60" TV and will be setting up my treadmill in front of it to lose 20lbs. Perfect excuse
for an upgraded pc to a) stream my TV channels from my wonderful HDPRIME and b) play
games like witcher 2, skyrim. 45FPS is fine. I like my rig pretty quiet when watching TV.
Also heat kills electronics over time so I appreciate good airflow.

I have a AMD 945 and XFX 6670 + DVD +
COOLER MASTER eXtreme Power Plus RS500-PCARD3-US 500W
to put into the chassis.

I just bought CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1866 (PC3 15000) and
Three cougar 120mm fans - plan on using 2

I want to buy a 990 MOBO for upgrade path.
Here is my thoughts

Case =V3 Black Edition ATX Mid Tower Computer Case - $30 Microcenter
ASUS M5A99X EVO AM3+ AMD 990X SATA 6Gb/s USB 3.0 ATX AMD Motherboard with UEFI BIOS - $120
(I like the 4 pin fan + e-sata).
Cooling COOLER MASTER Hyper 212 Plus RR-B10-212P-G1 - $30
60GB OCZ agility 3 - $50
MS Win 64 Bit - 100

$300 for a decent rig with upgrade potential next year for a better AM3+ that can really stretch out
the memory etc.

Please advise away on where to put my $3-500!