Motherboard - I'd go with something like an MSI Neo4 Platinum NForce 4.. (Check my signature)
RAM - I'd check out Corsair RAM. Whether you want budget RAM (ValueSelect of Corsair) or just great quality for extra (XMS of Corsair). I don't know how much difference you'll notice honestly, but someone else here can tell you I'm sure.
Processor - You can get a 3200+ Venice for less than the cost of that (about 197 on Newegg), so I'd go for that. 3200+ is still considered fast and very good. A Venice core is the best performing core in AMD Processors right now.. and runs the coolest.. so, stick with Venice.
Graphics Card - I know your gonna kill me, but this is going to cost a bit.. hehe. If you want to play games at high settings and have this true for a while, I'd suggest the 6800GT of Nvidia. It will do you wonders.. trust me.. hehe..
Case - The case I have.. and its AWESOME. Its very beautiful and I think the size might catch you off a bit at first.. its pretty large for a 'midtower'.. hehe.
All the same, a beautiful display and with the right stuff, it will truly make your friends drool..