Yes make sure to get a good PS. An extra $50 to $75 is worth it for a gaming rig. It will ensure a good, well-regulated supply of clean power to the system. As far as cases look for a tool-less design with a slide- or swing-out MoBo tray. Any "P4" capable ATX/ATX2 PS will fit in an ATX case.

"That's some catch, that Catch-22." "It's the best there is." M22ti VP150 EP350 QS8 M3Ti