What you may need--and this does take the pressure off those who do know their stuff--is the opinion of some one who doesn't know their stuff. After all, it sounds like you do.
This system is solid. As an AMD machine, what else would you do? An FX CPU? Waste of your cash: the 3.5K+ will do the job, which leaves the vid card, which you can later change. As to the choice of AMD over P4, and the A8N-SLI D MOBO, these are a matter of character (leaving $ out of it). First, test results for the 64 are impressive. Second, the design looks right (or at least interesting). Finally, P4-line is running out of gas (its my MBA), and simply put, there is just more scope for imagination with AMD these days--Good Choice.
Now, bring in the hounds!