The first decision you will have to make when buying parts for your new cheap computer is which CPU to buy. Once you decide which CPU you will buy it is easy to choose a motherboards that will accommodate it. Because computer technology is changing so fast, it is never a good move to buy anything that is the best in its category. For example, Athlon XP 3200+ costs around $330-350. Athlon 3000+ costs around $170-190. By choosing to go with only around 6% slower CPU (the difference you will hardy notice) you can save plenty of money.

My recommendation for the best processor right now, considering price vs. performances would definitely be AMD Barton 2500+. This is exactly the CPU I currently have, and the speed that it provides for it's low price is simply amazing.

Back in the days my favorite CPU's brand was Intel. However things are changing and right now my favorite processors are AMD CPU's because of their great performances and lower prices compared to Intel. You will need a fan for these CPU's which you can buy here for only around $6.

BUDGET PC

You cannot go wrong with 2500 + AMD Athlon with Barton core. Currently it provides best performances vs. price for a budget PC. It should cost you around $70.

CHEAP INTEL SOLUTION!

 
Intel® Celeron 2.6GHz / 128k Cache / 400MHz FSB / Socket 478 / Processor
 

If you are very low on money you can buy this Celeron 2.6Ghz. It still has a lot of power and right now the only thing that might challenge this processor are the latest games. However this CPU will be on the top of the task for everyday computer work. It should also cost you around $75.

GAMING PC

Well I guess for the ultimate gaming experience you have to go with the latest and the greatest. However do not forget my recommendation above. Always go one level down and save a lot of money. Your a little loss of performance you will save a lot of money.

Yes I could easily recommend you a Athlon 64 FX 53 939pin that will cost you around $800. However, if you buy Athlon 64 3400+ you will save around $400 for a slight loss of performances, and you will still have 64bit compatible processor.

HOME THEATER PC/BUSINESS PC/MULTIMEDIA PC

My recommendation for other three types of PCs would be AMD Athlon 3000+. It offers more than enough power for an affordable price.