heres my advice-
1. Don't get that ridiculous 800+ watt PSU, just get the corsair 620 watt HX series PSU like I got, its award winning and more then enough power for what you will need, not to mention its 125 right now with mail in rebate
2. Heh that gfx card...hardcore ATI fans ::shakes head::
3. Why that ram? Might as well go G.Skill HZ ddr800 pc6400 ram since thats far more award winning, ur ram is so unknown it only has 1 review on newegg!
4. Keep in mind that I heard with OEM OS once u activate it, its automatically tied to ur mobo meaning u cant use the OS for another computer later on
5. Also for your case might as well just get a thermaltake armor which is the same price with mail in rebate, except its a full tower case which means more space which equals better ventillation and room. Not to mention Ive seen the antec 900 and it seriously felt like I could punch right through the crappy plastic glass side. Way too flimsy, i still say bad build quality...
6. Good mobo choice...Im going with the same, award winning!
7. Im going with the same award winning HD, but u might wanna get 2 and raid 0 since its so cheap