What watt is my psu should be?

[digibrush]

Hi everybody!
my system config is:
2 hdd sata seagate 160gb and 500gb,
audigy sound card(pci),
pinnacle pctv tuner card(pci) and
9500gt 1gb graphic card(pci-e),
2 optical drive hp and sony both dvd writer.
5 usb device with mouse
my Mb is d101ggc and cpu is 2.66ghz pentium 4(prescot)
I put 30% in capacitor aging box and
calculate with coolermaster psu calculator and the result is 338 watts
Is it ALRIGHT OR I HAVE TO ADD FEW MORE WATTAGE TO RUN MY SYSTEM PROPERLY?
thank you.

[Fabian]

Yes , Definately , you will Have to Add some more Wattage to Run your system properly , I would Suggest you to go for a good quality and high wattage psu , as then if you upgrade your graphics card or any component later then you will not be needed to invest again on psu

[Baani]

When calculating the Amp, do you add the Amp on each of the multiple 12V rails? or do you consider only one 12V rail which is actually going into the PCI-E's power slot?I guess you can go for some kind of addition which will make your computer more better..