Is this going to be a gaming build?
I would of course get 2GBs of RAM. Corsair would be my choice.
A western digital hard drive. A raptor if you have the money, but it's not necesarry. WD has a 3 year warranty on all their products I believe.
There are a few good companies for motherboards. Asus, MSI, DFI, Gigabyte.
For the video card, you can go all out and get the 7950, or 7900. Or you can go budget and get the 7600, or X1600.