When it comes to the power supply, the bigger the better. I have a 450W in mine. My system doesn't need it all, but I think it can have an affect in overall performance.
I have mentioned a few times about the
Antec Sonata case. Some people dont care to invest much in their pc case, others want a slick one. This one has great design, and is really quiet. Overall, you got a pretty rock solid system.
Buy some new games for that high-end video card.