Video cards are misunderstood creatures. They are evil creatures and they will eat your soul. Where was I? Oh yes, graphics cards. Here's the thing, if you are a PC gamer (and I'm not talking about bejeweled or minesweeper) then you need a cutting edge graphics card in your machine. Of course, graphics cards also tend to be the most expensive component of gaming PC, by far! You may buy an entire base-model PC for less than the cost of JUST a top of the line graphics card. If you did not catch that, I will reiterate: Imagine buying a cheap PC for your office. Now imagine buying an upgraded graphics card to put in that PC, and it costs more than the entire PC did. This is why video cards are soul eating, evil beasts. The expense is incredible, and unavoidable.
The reason we need graphics cards is simple: because everyone else does not. Rendering three dimensional images is something that takes a lot of processing power, and it's also something that most people do not need to do. If they average person required their computers to render three dimensional images of emails and spreadsheets, or people they spoke with over instant messaging systems, the capability would likely be build into our CPU processors. As it stands though, a relative minority of those who use computers actually need this capability, which makes it something of a specialty item. Think of it in terms of buying an automobile. Most people are fine with what the dealership has on the lot, but PC gamers are going to the dealership and saying they need a monster truck with 60 inch wheels and a suspension you could drive a Volkswagen under. That's a custom job which will cost us dearly.
Still, there is an advantage. PC gamers are always at the cutting edge. Only poorly ported games look better on a console system than the PC. Console systems have graphics processors that are outdated within two months of the initial console launch. Xbox 360 and PlayStation 3 are years behind PC graphics capabilities at this point. When new console systems come out they will be the toast of the town for a few months, but most of their product cycles will be sent behind the curve on graphics too. PC gaming is an expensive hobby but it means we get more out of our games than anyone else does. Today's video cards have specialized chips to process everything from shadow rendering to particle effects like smoke. Tomorrow's graphics cards will bring even more realism to PC gamers.