That chart is pretty good actually.
Never by a rosewill case. Ever. they suck, the few people I haven't been able to talk out of them hate them, and your case is the single component of your PC that you will have the longest.
I tend to prefer Intel over AMD personally, but you definitly get more bang for your buck with AMD.
$500 is very low for a gaming PC, especially if you factor in operating system cost. You can build a pc for that price, but it will not be a high end machine.
Here's where I would start with a budget in mind, but not limited to $500: Case:
Cooler Master CM 690 II $89.00 http://www.newegg.com/Product/Product.aspx?Item=N82E16811119216
Roomy, looks nice inside and out, rails and toolless screws for almost everything. There are better cases available, but there are no better cases in that price range. Motherboard:
Asus P7P55D-E $109.00 http://www.newegg.com/Product/Product.aspx?Item=N82E16813131634
Decent solid board with USB 3.0 ports and 6GB/Sec SATA ports. you wont need either initially, but 2-3 years down the road that will be important for continued upgradeability. Especially when the affordable 6GB/sec Solid State drives show up. This is a socket 1156 motherboard. There is also the higher end Socket 1366. The only advantage you get with socket 1366 over 1156 is that socket 1366 boards have 6 ram slots as opposed to 4 here. The processor prices for 1366 are usually about $100 more. Processor:
2.93 GHz Intel Core i3 Socket 1156 dual core $114 http://www.newegg.com/Product/Product.aspx?Item=N82E16819115222
This is the low end of the Core i3 line, but plenty fast for gaming at the moment. You could throw another $100 at it and get a comperable i5 Quad core http://www.newegg.com/Product/Product.aspx?Item=N82E16819115067
Or $200 more and get a Core i7 quad core with hyperthreading for a total of 8 logical cores http://www.newegg.com/Product/Product.aspx?Item=N82E16819115214 Power supply:
Antec 750 watt $89 after rebate http://www.newegg.com/Product/Product.aspx?Item=N82E16817371025
We have about 200 of these at other work. They are reliable and have a decent warranty. I tend to prefer Enermax power supplies in my personal builds, but the budget prohibits that here. Ram:
Corsair 4GB ram kit 2x 2GB $99 http://www.newegg.com/Product/Product.aspx?Item=N82E16820145251
Go with windows 7 64 bit, and eventually get a second one of these kits as funds permit. Video card:
If that 4300 is PCI express, you can use it short term. If it is AGP, you are screwed and will need a new card. Eventually you will need a new card regardless. You can still get a 9800 GTX for around $134 http://www.newegg.com/Product/Product.aspx?Item=N82E16814130339,
though they are starting to get a bit long in the tooth. There are equivelent ATI cards avaialble as well. I know the Nvidia side better than the ATI side. if you download and run GPU-z and post a screenshot here, we can tell you exactly what type of card you have. I'm going to leave videoo card out of the price total for now.
Optical drive: 22x LG SATA DVD RW $17 http://www.newegg.com/Product/Product.aspx?Item=N82E16827136180
optical drives are dirt cheap these days, no need to try and use the old IDE drive. also less airflow restriction from big ribbon cables
Hard drive: WD 320 GB SATA hard drive 7200 rpm $47 http://www.newegg.com/Product/Product.aspx?Item=N82E16822136098
You may have a working hard drive, but hard drives will eventually fail, and 5 years is getting pretty old for a drive. That and you don't want to mess with IDE anymore. There are bigger, better drives, but you are looking at around $100 for a really large one, or $140 for a really fast one.
Total so far:
$564 without the video card. Expect to pay $100 more for windows 7 64 bit home premium http://www.newegg.com/Product/Product.aspx?Item=N82E16832116754
unless you have an educational license source or something similar. That would allow you to use the full 8GB ram when you buy the second ram kit.
You should also budget an additional $250 or so for a really good midrange video card.
If you don't have one handy, grab a tube of artic silver as well, just in case.
You won't need any other additioanl cables or fans or anything. Everything else comes with the case or the motherboard.