Okay...so.
1.Go with the Intel processor since they're currently better than AMD's. I recommend a Core Duo E8500 or 8600 or for the long run quad core Q8200 or Q9400.
2.For the motherboard maybe you should try something with a P45 chipset. Something not too expensive but good.
3.For the graphics card i would go with ATI with the 4850 toxic or 4870 (good price and perform really well. If you chose Nvidia go with the 9800gtx. Good thing about newer cards is that later on you can buy another one and connect it with your old one (SLI/Crossfire) but it has to be the same series card.
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For crossfire(ATI Cards) you only have to have a motherboard with 2 x16 PCIe ports)
For SLI (Nvidia Cards) the motherboard has to be SLI ready that means you can probably read SLI ready under motherboard specifications.
3. Don't buy used if you have money for new hardware.
4.I recommend a LCD screen since CRT's take too much space. And about the CRT's are "speedier" than LCD's is not important since its a matter of miliseconds and your eye can't really tell much difference. I recommend a 20 inch LCD something like Samsung.
5.For the case that's the part where you save money. You can buy a good case for little money and you can even take a used one lol. Buy something from chieftec or thermaltake or some other famous case brand.
6.Hard drive depends on what you're aiming for:
1) Store a lot of data(songs,movies,shows,etc.) buy a big hard drive 500-640GB. Buy a Seagate or Western Digital. Keep in mind that it has 7200rpm.
2) Fast access to data (gaming and so but also to store data) buy a Western Digital Raptor with 10000rpm.
7.Sound card: you can buy it or you don't have to xd. Most motherboards have a integrated sound card which is just enough for normal pc use.
8.Keyboard: i recommend something from logitech. Something that's not to expensive and suits you fine.