What should i put in my new pc? What Graphics card, cpu, what case, power supply etc.... whats the best?

I'm gonna build a new computer, i know a bit about this sort of stuff but i would like to know your opinion on what is the best stuff out there atm. ThanksWhat should i put in my new pc? What Graphics card, cpu, what case, power supply etc.... whats the best?
ram : 1 Gega ddr2


processor: 3.4 dual core


vga: 256 ATI


HD: 350 Gega


Network Card: Any Kind


mouse: As u Wish


Keyboard: As u wish


Mother board: Support dual core and ddr2


And don't get built in in the mother board(vega or sound)