For Starcraft 2 this is what you need to play Recommended settings (not optimized settings mind you, so this is to play the game without max graphics)
PC: Windows Vista/Windows 7
Dual Core 2.4Ghz Processor (you chose a 3.0 quad, you're fine)
2 GB RAM (you chose 4, you're fine)
512 MB NVIDIA GeForce 8800 GTX or ATI Radeon HD 3870 or better (you will need to buy a vid card, the radeon you listed should work alright. )
I would get this board of the ones you listed: Newegg.com - ASUS M4A89GTD PRO AM3 AMD 890GX HDMI SATA 6Gb/s ATX AMD Motherboard
The build that Fat.Clown recommended looks great, the only thing I'd point out is that the case only comes with one fan, and if you're going to pump out a quad core with that gfx card (and running on that mobo, which is known to run hot) you'll probably want to get more fans for the case (it can support quite a few) or get a case with more cooling.
And I personally never use home edition windows since it's the worst for upgrading but that's a personal preference.
Even with his build you will still need a SATA cord for the bare drive.