Gigabyte GA-890GPA-UD3H specs
GIGABYTE - Motherboard - Socket AM3 - GA-890GPA-UD3H (rev. 2.1)
1. 4 x 1.5V DDR3 DIMM sockets supporting up to 16 GB of system memory (Note 1)
2. Dual channel memory architecture
3. Support for DDR3 2000(OC)/1333/1066 MHz memory modules
So, DDR3 1333 Mhz RAM is preferable. What you have selected is DDR3 1600 MHz RAM ($54)
See: Newegg.com - CORSAIR XMS3 2GB (2 x 1GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) Dual Channel Kit Desktop Memory Model TWIN3X2048-1333C9
(order two if wanted)--better quality, guaranteed RAM.
1. North Bridge: AMD 890GX
2. South Bridge: AMD SB850
AMD 890GX SB850 Chipset Debut: Phenom II X6 Ready
Tuesday, March 02, 2010 - by Marco Chiappetta in Motherboards
AMD 890GX SB850 Chipset Debut: Phenom II X6 Ready - HotHardware
"The 890GX is a nice step forward for the AMD platform. In terms of features, an argument can be made that the 890GX / SB850 combination is the most advanced desktop chipset currently available. The Radeon HD 4290 IGP is one of, if not the most powerful integrated graphics solution on the market and the SB850 is the first Southbridge to natively support SATA 6G, even if the latter doesn't mean much in terms of performance at this point in time."
HDD selected is 1TB at $63. (Compare Newegg.com - SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
Largest I would go with, at present is 750GB, like the one here: Newegg.com - Seagate Barracuda 7200.12 ST3750528AS 750GB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
Two smaller is preferable to one larger of equal capacity, especially cache size, like 2 X Newegg.com - SAMSUNG Spinpoint F3 HD502HJ 500GB 7200 RPM 16MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
-- 32MB cache total, double the number of needles seeking data. More money but better performance -- your choice.
Or, at 7200 RPM 64MB Cache SATA 6.0Gb/s
Newegg.com - Recertified: Western Digital Caviar Black WD6402AAEX 640GB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive
And I'd go with Newegg over Amazon any day!
Ultimately, it's only you who can decide.
Best wishes and welcome to the world of custom-builds -- it all depends on what you want(but you asked)!