If you posted an exhaustive spec list and also the brand/model of the power supply, people could give you opinions on how well the PSU matches up to your power load. That would include CPU, video card, all drives, all cards, and we know it'll have four 512MB memory modules.
Here is my slower computer for example:
1GHz Duron
one 512MB memory module
Radeon 7500 🙁
one 15000rpm SCSI drive 😎
one optical drive
one floppy drive
56k PCI modem 🙁
memory-card reader
300W Inwin/Powerman power supply with 15 amps on the 12-volt rail. Comfortable. But then again I'm a power-supply overkill zealot 😀