Well here's what I do when making my computers:

I usually goto www.tigerdirect.com, they have a large supply of computer components and it's a good source for quality stuff. They have motherboard/cpu bundles that save you some money and the good thing about it is that the cpu will work with your motherboard. But anyhoo.

I would get at least a 1.4g AMD, I don't like Intel that much since the AMD's go faster and are cheaper (Intel uses their logo to jack up the price).

Get a Radeon or Geforce video card, at least a 64mb.

Sound card, doesn't really matter.. I can't really tell the difference between the quality anyways.

Mouse- get a optical one.

Keyboard- internet based is nice.

Moniter at least a 17", make sure it will support the resolutions you might be using.

Harddrive- 60g at least, try for the 7600 rpm or higher.

CDROM 56x. CDRW anything above 10x write is good enough. Floppy drive. Zip if you use it a lot, get a 250- I've heard the new ones (750?) dont write to 100 discs.

Ram- at least 256k

Network card- 10/100 at least

Fan- At least one fan for the components, either attached to the back or on a HD.

Case- ATX is the standard, make sure theres a power supply with it. Also see if you can get one that has cooling components.

Cost for what I listed: about $600