Whoop, nevermind. When posting, it doesn't show sigs...
So first off, you're going to need a lot of parts, and $500 may not be enough. I'll try though.
Video Card- You're going to want to stick to 128MB of memory. I'm not sure if you want Nvidia or ATI, so I'll do both. ATI- Go for the 9600 Pro or the 9800 pro. Nvidia- Try for the 5900 XT, about $200.
Memory- You have good memory, but try to get to a Gig of RAM. 512MB cost around $90 for good prices ones.
Processor- Again, intel or AMD. Intel- try for Pentium 4: 2.6 GHz around $100. AMD- 2800, around $100 as well. Also, AMD has lots of numbers and priceranges. If 2800 is too much, try 2700, 2600, 2500, ect. Cheaper and cheaper.
Sound Card- You have to get a Creative Audigy 2, or 5.1. Try for a 2 though.
Drives- Always get Lite-on drives. 52x burner and reader is really good right now. They're about 30, $35 a piece.
Motherboard- Toughy. I can't really help you out in this category. You can always get the one I'm getting, the K8V SE Delux. It's compatible with pretty much everything at this point. But it's $123, so hopefully somebody else could help you here.
Floppy Drive- 1.44MB, 3.5 inch. Sony's a good brand, but find whoever you like. They're about $10 a piece.
Hard Drive- If you're going to be playing lots of games, go for
atleast a 80 GB Hard Drive. And you must go with
Seagate!
Case- The final touch. Find a nice shiny case for yourself. Be aware of the cooling and PSU it contains. You want the PSU (Power Supply Unit) to be atleast 350 Watts. And cooling to have atleast 2 fans, if not more. They're a huge range of case pricing, so find one you like.
That's it! You owe for writing this much!

* Passes out *