I'm going to pick you apart a little. Hope you don't mind my suggestions.
Motherboard, I'd go with the one that own. It's AWESOME, and Asus has been a not as good as they used to lately. Customer service sucks.
MSI K8N Neo4-F
If you ever get into overclocking, I think what you'll want to do is either go with the Athlon 64 X2 3800+ or the 4400+. If you can afford it, get the 4400+. It has 1mb of L2 cache on both cores. If not, go ahead and downgrade to the 3800+. You won't feel a difference (hardly. I mean, it IS clocked higher)
Your ram looks good to go.
Your video card is one that is kindof akward. If you are trying to game, there's no reason not to spend $20 extra bucks and get the 6600GT which is WAY more powerful.
Your case is okay, but the power supply is going to suck. I'd get this one.
But since you have 2 power supplies now, you may want to change to a case that doesn't have a power supply.
If you want to know why I've done any of these things to change your setup, feel free to ask, but in my opinion, these are all things that needed to be fixed.