Ok one question, if you are using the ATI gpu then why get the SLI deluxe mobo. You are just paying extra money for something you won't fully utilized. You should get a Crossfire edition mobo or a single pci-e mobo if you're not into dual gpu set up.
ASUS A8N5X Socket 939 NVIDIA nForce4 ATX AMD Motherboard for around $80 compare to your choice that is $230.
looks fine bar the mobo. it always makes me laugh when people buy SLI capable mobo when using an ATI card. unless there is a specific capablity of that board avoid it. your power supply should be o.k but then again always buy one that has alot of headroom.
I have an ATI Card and an SLI Mobo, why did I buy it? Because it overclocks like a son of a gun, better than any other motherboard. All the best motherboards are SLI right now, so if you're overclocking, it's worth it.