i like your setup, but go with corsair xms series ram, and get 2 sata 36gb 10,000 rpm hard drives. i would recommend wd raptors. configure them in a raid0 array and that machine will be SMOKIN. your hard drive and ram are the only two bottlenecks in that system, and if you do what i said then they wont be bottlenecks anymore. buy it all from newegg because newegg has excellent prices, excellent shipping, and is just an all-around reputable retailer. you could save a few bucks using another site but it might be a mislabedled product, it might have extra shipping costs, etc. newegg all the way.
edit: and that case is good. dont go with a smaller case, that case is excellent and will have great airflow.
edit: and that case is good. dont go with a smaller case, that case is excellent and will have great airflow.