looks good to me.
-8gb is truly more than you need for gaming. I would start with 4gb and add 4 later if needed. this will free up some space in your budget as well.
-That video card will not crossfire, just pointing our because you said maybe in the OP. you should get something a bit more powerful especially if you want to play newer games. check out the radeon 6450 or 6550, these are fresh inhttp://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007709%20600083901&IsNodeId=1&bop=And&Order=PRICE&PageSize=20
edit: for something that will crossfire, you will need to spend ~$150
NVIDIA has lower priced cards that will SLI such as this gts 250 http://www.newegg.com/Product/Product.aspx?Item=N82E16814150513