[Templar]

Building a PC is not difficult, I've done it quite a few times and was successful on my first attempt. For your budget, you can build a pretty damn good desktop.

Power supply, motherboard, RAM, processor, hard drive(s), graphics card, operating system. That's pretty much it. I didn't go with anything too fancy, like a fancy sound card or a Blu Ray drive or anything. Make sure the power supply supplies enough power for all parts, especially if you're going with a fancy processor or high end graphics.

You can buy a motherboard that has integrated graphics, but if you do any sort of real gaming or video editing you will want at least one dedicated graphics card. Going into nVidia SLI or something similar with two cards, you'll see your budget disappear pretty fast. I was somewhat conservative on this on my last build, but the card itself still has two GPU's.

I also recommend solid state hard drives. More expensive, but MUCH faster. At least use it for your most commonly used programs and your operating system. Windows is loaded on my PC before I can get my ass situated in my chair after I turn the computer on.

Eventually I will think of more, but I built my PC a few years ago and it's still rocking. I'm considering upgrading the graphics card though, maybe...