Building a new gaming pc

I would like to know what kind of stuff do i need to buy to make me a good/decent Gaming pc that will be able to run a few of todays games with out problem.

thank in advance

>>7
The only two advantages of PCI Express:
1. Bandwidth, which you don't need as AGP8X is far from exhaust.
2. SLI, which you don't want to do as it's a waste of money and a bad idea for an upgrade (in the future, you'll want an all-new video card with better effects and features, not just more raw power).

This leaves us with a total of 0 reasons why PCI-E is worth having. Since it's more expensive, and the cards using it are more expensive, it's not advisable.