Ok, well I've built a few systems myself, and have had my fair share of bad luck.
Pointers:
1. Don't buy ASUS or SOYO products, not only do they fail often, but the companies don't back up their product well at all.
2. You'll need a PSU (Power Supply Unit), with atleast 300watts for today's systems.
3. Benchmarks are Nvidia biased. If you need graphical proof, look at framerates from popular games, that's where the true testing is.
I would recommend buying an MSI motherboard. Not only does there company back their product 100%, but they typically have great BIOS setups. I would also recommend the 9600XT made exclusively by ATI. Off-brand makers have less reliability. Don't forget the little things, like a mouse, keyboard, etc... they typically cost money as well.