For you people who will be doing general-computing tasks such as word processing, web surfing, etc, the Celeron/Duron will do you fine when it comes to performance. In fact, if you're a power user who's on a budget and will be doing a lot of gaming, these processors will also be able to handle the load, although the experience won't be as indulging as with the high-end counterparts of these processors (no playing Quake III at 652.3 fps...)

Intel Celeron
The Celeron processor has been Intel's answer for the low-end market. The versions that are currently available are 400MHz-533MHz Celerons, and 533MHz-633MHz Celeron II's (or sometimes referred to as Celeron A's). Basically, the original Celeron is the trimmed-down version of the Pentium II, while the new Celeron II is the trimmed-down version of the Pentium III. They both run on a 66MHz bus, meaning that all system devices, such as the system memory, runs at 66MHz (which is actually what most of the original Pentiums run on). They both have 128KB of full-speed, integrated L2 cache (if you don't know what this means, try reading what I said before about caches, and if you still don't know, don't worry, it's just something to boost performance =). So, you ask, what's the difference? As mentioned before, the Celeron II's are trimmed-down versions of the new Pentium III's, which mean they have the same SIMD instructions that are built-into the Pentium III, increasing performance for applications and games that support these instructions, are built on the same .18-micron process as the Pentium III, allowing them to run at higher speeds and at much cooler temperatures and use the FC-PGA socket, which again, is what the Pentium III uses. The older Celeron's, however, don't have SIMD instructions, are built on a .25 micron process, which means they can't go as fast and run a lot more hotter and use the older PPGA socket which Intel plans to abandon. So, which should you buy? Personally, I would get the new Celeron II's because of the .18 micron and the added SIMD instructions and mainly because the price difference is very small between the Celeron II and the original Celeron. Also, the fact that to get a motherboard for the Celeron II, you would need to get one with support for an FC-PGA socket, which is a bonus if you wish to upgrade your CPU to a newer one in the future because Intel is making all their new CPU's using the FC-PGA socket.

AMD Duron
The alternative to the Celeron (or Celeron II) is the new AMD Duron processor, available in 600MHz-700MHz versions. The Duron is a trimmed-down version of the new Athlons. It only has 64KB of full-speed L2 cache (compared to the Celeron's 128KB) but it has 128KB of much faster L1 cache (compared to the Celeron's 32KB). It uses the new Socket A design that the new Athlons use, which means you can buy the same motherboards for the Duron as you would for the new Athlons. Also, the Durons use a 100MHz Double Data Rate bus, which basically means that the CPU talks to the system at 200MHz (compared to the Celeron's measly 66MHz bus). These additions make the Duron perform a lot better than the Celeron (and even the Celeron II's).

Bottom Line
Personally, I would opt for a Duron over the Celeron, as the Duron gives you much more bang for the buck and the fact that they have identical prices; however, the Duron is a new processor and uses a new Socket A design, which makes it hard to find the CPUs and motherboards for the CPUs. Also, the fact that all new AMD processors suck up about twice the amount of power than Intel processors does mean that you'll also have to spend a premium on a quality case and power supply, which adds to the price of the system. So, the general rule is, if you're really tight on cash, get an original Celeron, if you've got a little room to work with, get a Celeron II and if you've got quite a bit of room to work with, get a Duron. If you've got even more room to work with, it's time to take a look at some of the higher-end solutions.

On to: High-End Solutions