Welcome to the wonderful world of PC gaming. We're sure you'll like it here.
First off, here is the Escapist's usergroup for PC enthusiasts and such. Most, if not all, of us build our own PCs, and are quite knowledgeable about the whole process. http://www.escapistmagazine.com/groups/view/PC-Builders-and-Hardware-Group
Second, as has been said many times, we need information. This is like saying "I need a gaming device, what do I get?". It could lead to suggestions to get a Xbox 360 when what you wanted was a portable device capable of playing most current gen games, with a good battery life and that costs less than $300. The 360 does not work in that case.
Information that will be needed:
1. A budget, as has been said many times. How much would you like to spend? PCs can range anywhere from $300 to $5000. Without any idea of where to put you on the budget, we can't really pick the most cost effective parts to get you what you want.
2. Are you willing to build it yourself, or would you have to buy prebuilt? Building yourself also includes finding your local tech store and having them build it for you, or having a friend/family member build it for you.
3. Laptop or PC?
4. Do you already have peripherals like a monitor, keyboard, mouse and speakers? Or would you have to purchase those?
5. Where you'd like to see the budget allocated. Least important, and you can probably skip, but what would you like the build to focus on? Maximum FPS in games on highest settings? Fast loading times? Being quiet whilst running well? Putting more money into certain components will increase the capabilities of the PC in certain regards, whilst the budget sacrifices in other areas will reduce what you get out of it in others. Some idea of what you'd like to focus on would be nice, but is not necessary.