Processor choices are a bit more difficult now then they were before. It is still really a choice between an AMD and an Intel processor. The difference really comes in how many cores there are in the processor and its relative speed. Each company now has a performance rating system that isn't really easy to compare. Due to the complexity, its best to refer to my links below for a more detailed explanation of CPUs for budget and uses.

1. AMD Performance - Phenom 9850 Black Edition
AMD has fallen pretty far in terms of high performance processors. The Phenom processor lineup was designed to try and compete with the Intel Core 2 Quad lineup. The Phenom 9850 features four processor cores on a single chip with a default clock of 2.5GHz. This is step up from the previous first generation Phenom processors but much lower than Intel's offering for the high end. The Black Edition of the processor is clock unlocked though for those wishing to try and push as much performance from it as they can. The one big advantage that AMD has of course is price. This processor is roughly 1/4 the cost of Intel's Core 2 Extreme lineup.

2. Intel Performance - Core 2 Extreme QX9775
If absolute speed is your goal without the worry of cost, then the Intel Core 2 Extreme QX9775 is the processor to look at. This quad core processor runs at an amazingly fast 3.2GHz speed and comes equipped with a gigantic 12MB of cache memory. This gives it out of the world performance in just about any application on the market. Of course, the price of the processor is more than some complete desktop computer systems that still offer very strong performance.

3. AMD Value - Phenom 9850 Black Edition
AMD hasn't released any new processors in the past few months. As a result, the Phenom 9850 Black Edition price has fallen below the 250 value threshold. This makes AMD's highest performance consumer desktop processor also the best value processor. While not as fast as the Intel Core 2 Quad models on the market, it certainly provides a very competitive product for its price. And if you want even more, the Black Edition is always clock unlocked for easy overclocking.

4. Intel Value - Core 2 Duo E8500
While quad core processors are certainly in the headlines more for desktops, their frankly aren't many applications that can take advantage of all four cores. Unless you are doing desktop video or heavy multitasking, a dual core processor is generally going to provide you with a better overall experience. The Core 2 Duo E8500 is one of the fastest dual core processors from Intel on the market right now and comes with an extremely affordable price tag. And if that 3.16GHz core speed isn't fast enough for you, the series is well known for its bus overclocking for extra performance.

5. AMD Budget - Athlon 64 X2 6000+
For years, AMD was the budget alternative to Intel processors. They jumped out of this with the original release of the Athlon processors, but they have slid back down. Because of this, AMD has slashed prices offering some very strong performance for very little cash. The Athlon 64 X2 6000+ is currently the fastest of the older generation processors topping out at 3.0Ghz with two processors cores and support for DDR2 memory.

6. Intel Budget - Pentium E5200
The Intel Pentium E5200 is actually based around the Core 2 processor design. In fact, it uses the same 45nm core as the extremely popular Intel Core Duo 2 E8000 Wolfsdale processors just with lower clock speeds and caches. The main reason for it to retain the Pentium name is to separate itself from the more performance oriented versions as a budget oriented product. This 2.5GHz part has more than enough performance for all the basic computing tasks and can even handle some of the higher end stuff, just not as quickly.

next to consider is Memory (RAM)

Most desktop computers now use a type of memory called DDR2. Some high performance ones might use DDR3, but this is quite expensive. Avoid systems using the older DDR memory standard. In terms of amount, it is best to have at least 1GB of memory in the system and preferably 2GB. Memory speeds can impact performance as well. The faster the memory, the better the performance should be. When buying memory, try to buy as few DIMMs as possible to allow for future memory upgrades if needed.