The key to finding the right system is to locate one that meets you needs, but doesn't exceed those needs at a higher price. At one time, I would have recommended buying a PC with the fastest processor that you can afford. These days, however, almost any processor on the market is capable of meeting the needs of most families (unless you're playing some heavy-duty games). The only exception is the Intel Celeron, which is somewhat less capable when it comes to graphics.
Make sure your PC comes with enough memory - no less than 128MB of RAM, and preferably, 256MB of RAM. And you'll also want to purchase adequate storage space - today's PCs come with 20 GB and larger hard drives. A 20GB drive is probably just a start, while a 40GB or bigger drive will be able to hold a number of music and data files. If you plan on using your PC to perform video-editing, you'll want an even bigger hard drive. You may also want to purchase a system with a CD-RW drive that lets you burn music and data CDs.
Generally, today's systems rip through computing tasks so fast that differences in performance are, frankly, not important for most applications. So rather than focus on speed tests, we recommend that you consider how well a system is designed and integrated, and how comprehensively it satisfies your needs, or the needs of your users.
It's a good idea to see how much room a system offers for future expansion. While some of you will probably never crack open your PC to add enhanced or new capabilities, others will start to add components and expand features right away. Look for open slots for adding internal cards, and USB ports for supporting external devices.
What are your key requirements? Before plunking down good money on computer equipment, you need to determine what your requirements are. For example, if you will mainly use a word processor to write letters, you won't need a system that supports high-end graphics. And if price is your main concern, you'll be getting a different system than someone who want's a cutting-edge system that will play the latest games. Identify the software and applications that you want to run before you make a decision on a new PC. Keep in mind that if you need to, you can upgrade individual components and systems later.
Last, make sure to check out a system's warranty. Some vendors offer on-site support that may be useful should something should go wrong. If you are unsure about your abilities to trouble-shoot your new PC, you may want to pay extra for these services.

computers - Finding the Right Desktop PC