Munchie,
Not sure if you have been to this site
http://www.sharkyextreme.com. They have good articles detailing specifications and pricing on the component level. They also have Buyers Guides (usually updated monthly) that are tailored to value (lower end), hi end (middle of the road) and extreme systems (the best of the best of the best, sir).
Anyways, here are the links to their buyings:
Value ($1,000 price range)
http://www.sharkyextreme.com/guides/MVGSBG/article.php/3550661Hi end ($2,500 price range)
http://www.sharkyextreme.com/guides/MHGSBG/article.php/3552841Extreme ($4,000 price range)
http://www.sharkyextreme.com/guides/EGBG/article.php/3529251They take into account new monitors, speakers, keyboard, mice, etc in the price points of those systems. If you have a decent set up of peripheals, then you may not need those. Should be a decent starting point for you tho.
BTW, the mobo you have selected rocks. I am running an AMD 4000+ on that same board. DON'T install the nvidia ide drivers tho. (/me kicks self in butt for four reinstalls of Win XP to start)