extreme edition p4? do you read anything on the net other than intel marketing? As people have mentioned, just don't do that. Go AMD, especially for SLI, and get an nf4 chipset mobo. I can understand people buying Intel, just because that is what they've always done and are stuck in the intel groove that intel marketing loves to grease. I can't understand anybody paying for extreme edition prices. The only people who know what EE is are going to belittle your epeen because it isn't AMD.
You won't need a 600 watt ps, look at my rig. Sure, that p4 ee is a poorly performing, inefficient space heater, but you still shouldn't need a 600watt PS, unless it is from a crappy vendor whose 600watt ps is no better than a 350watt ps from somebody good.
On the case point, I don't really recommend the p180 for your rig, as somebody else did. I'd go for something with more useable space, especially if you're going to be in and out of the box often. Don't get me wrong, I like my p180 just fine----now that it is all put together. Getting to that point, and changing it around now and then is a royal pain in the rear. The split chamber design, while great for airflow/cooling/noise control, is a big step backwards in ease of use/installation for a case.