here are the prices.. they both the same :-\
X800 XT
http://www.bestbuy.com/site/olspage.jsp?tab=1&type=product&id=1077624680596&skuId=6366602&productCategoryId=cat01151
6800 Ultra.......
http://www.bestbuy.com/site/olspage.jsp?id=1083712380517&skuId=6684643&productCategoryId=cat01151&type=product
.
X800 XT
http://www.bestbuy.com/site/olspage.jsp?tab=1&type=product&id=1077624680596&skuId=6366602&productCategoryId=cat01151
6800 Ultra.......
http://www.bestbuy.com/site/olspage.jsp?id=1083712380517&skuId=6684643&productCategoryId=cat01151&type=product
.