For that card the 500 watt sli psu would do okay. It would have extra 6 pins and only has 2 sata cables according to reviews. It is always good to think about future upgrades and to be prepared for them. Shuttles are low end quality. If money is tight then I would go with 4 gb RAM all same numbers. Many complained about mobos going bad right away. CoD:WaW requires more resources to play smoothly than the cod 4 did.
When are you coming in to get your BK tags on?