Ya, you want to go with a 450w power supply at least. Im not going to go into much details here but you want to build with a mind towards upgrade-ability. Much of the stuff that is out now is just about obsolete. You want a mother board that can handle DDR2 memory and PCI-e slots. Dual core processors seem to be the rage now, altho Im not to much up on them atm.
DDR, AGP and PCI are all going the way of the dinosaur. You can still get new components that support all that, but that will be it. Not much room for future upgrades.
As for ATI vs Nvidia... well, you get as many different opinions on them as there are people on this forum. I used to always run nvidia but I just recently bought a radeon x1300 pro since it was the best I could find for an AGP slot and the price was good. I like it just fine.
The vid card was the last upgrade Im going to get out of my current rig. Which is 4 years old now. Next is going to be another complete rebuild with all the new generation hardware so I can upgrade that for another 4-5 years.
