If playing some games or productivity applications... you may find 8GB of RAM to be not enough. Cheap upgrade later if that ends up being the case though.
Oh, and while 500W is probably fine for that system... I'd still go higher for more clearance. Ie, 600W or 700W. As I'm not sure the new AMD cards will run on a mere 500W PSU.
Edit: From what I'm seeing... New AMD Polaris cards aren't going to be power behemoths. http://www.tweaktown.com/news/52617/...024/index.html