If you're going to have a P4 2.53 system and a Radeon 9700Pro, then you should make sure you get a decent power supply cause that's going to be drawing quite a bit of juice. I would make sure to get at least a 330-350watt psu if not more (something in the lines of Antec, Sparkle or Enermax). The case will depend on what psu you want cause you can usually get a decent case with one of these psu's. I would also suggest one of the Antec cases like the Performance Plus 660 or 880, but since Ncix doesn't have that, then the sx1030 with 420watt psu might be more than you need, but it will be alot better than limiting yourself.