When considering your choices do consider your end functionality. In other words, do you want a gaming monster? If yes, probably go for AMD. Do you want a cheaper system, that is fast and gives you more for your buck? AMD. Do you want more transactional power, better database handling, and willing to burn a few xtra bucks for the faster mobo bus and the latest hyperthreading tech? Then go to the Intel consumption mass.
My advice is that if you are looking for a fast system, that can do general stuff, then go AMD, great for graphics, games and all the general computing stuff. Now they even have 64bit tech for pc's; which you can use with some Linux distros that have already been ported to 64bit platform.
On the memory, I think DDR RAM is pretty much the standard these days....it goes as fast/high as 400/433 I believe. It's always changing. For Harddrive, consider SATA, gives you almost teh performance of SCSI, and the cheaper will be 7200 rpm, special edition 8MB buffer such as Western Digital....For the Video card....can get anything from decent to good to good high in the 100 to 200 dollars.
Sound? Some mobos support 5.1,6.1 channels surround built-in, but beware not all work as expected. Alternatively spent some $50 for a decent/good card with some good choices.
Cooling? Depending if it is for AMD or Intel? AMD is typically hotter than Intel....I am sure you can find good resources on the net for it.
Mobo? Again, depends on the processor....I have always built AMD processors....try different ones like Asus, Shuttle, Biostar, and some other ones can't remember...
Asus is top of the line, usually introduces the newest stuff, *unproven* technologies sometimes as they are leader in the arena, but again with new things nothing is granted. Shuttle usually adopts more conventional, tested techonology, so it is a cheap and in most cases reliable player. Biostar is somewhere in between....that's just my opinion.
Do some more research and consider your choices ....I think with some 500-600 bucks you can build a nice system, especially if you already have some components such cdrom, dvdrom, cdburner, floppy, even some harddrive....
GOOD Luck...Hope it helps
