That's because technology moves at a fast clip. The high-end computers of today are the budget PCs of tomorrow. You really don't need to spend much to get a new, usable machine. But if you're ready to splurge, you can get a system unbelievably faster than your old one.
The first question to settle is: Desktop or laptop? Some people are choosing laptops as their main computers, thanks to portability and energy efficiency. You can learn more about buying a laptop PC in this buying guide.
For a basic family computer or high-end gaming rig, a desktop is still the way to go. They're less expensive, more customizable and easier to repair and upgrade.
The majority of buyers are fine with a budget computer. Any modern computer can handle word processing, Internet browsing and writing email. It's perfectly capable of handling even basic photo and video editing.