With the above configuration as is, I'd go with a lower end P3 or below...
You're obviously looking for a high end machine, you will need a more powerful PSU, I'd suggest minimum 350Watts. Once that's settled, grab yourself a powerful P4, the 2.6-2.8GHz 800fsb looks like a very good price/performance ratio.
A P4 easily uses 80+watts, a Radion 9800 another 50 or so, 50+ for a fast harddrive, 50+ for a cdrom, and we haven't even gotten into the motherboard and memory yet, nor looked at future hardware add-ons.