I've been a PC gamer for over 20 years now, and building systems just as long. The one thing that's never changed in all that time is the difficulty that goes into the decision of buying a new piece of hardware for your computer. This is part of the reason companies like Alienware, Dell, and HP do so well at selling pre-built computers.
The core piece to any gaming PC is its graphic's card, these little beauties are what power the pixels and polygons of your games. The faster and better the card - the prettier your game can look. But with so many choices and numbers, how the heck are you supposed to decide?
The boys at Gizmodo have created a guide to help solve just that.
The basic premise of their guide is simple - set a budget, understand the numbers, don't get caught up in specs, and trust the hardware websites. All very sound advice.
With manufacturers releasing graphic cards on a six to nine month cycle it's very hard to stay on the "bleeding edge" - it's not only hard it's expensive.
It seems like you ought to be able glean a linear progression of performance (or at least price) out of that alphanumeric pile, right? Not at all. How in the world are we to know that the 9800GTX is generally more powerful than the GTS 250, or that the 8800GTS trumps a 9600GT? A two letter suffix can mean more than a model number, and likewise, a model number can mean more than membership in a product line. These naming conventions change every couple years, and occasionally even get traded between companies. For example, I've personally owned two graphics cards that bore 9x00 names—you just won't see them on the chart above, because they were made by ATI. Point is: You don't need to bother with this nonsense.
Give the full article a read if you are looking to upgrade your PC to play some of the great co-op games the platform has to offer like Left 4 Dead, Dawn of War 2, or Trine.