As stated elsewhere, the PC 98 compliance standard has been fairly reliable in predicting the way that computer trends and software development are going. The PC 98 compliance standard is very well respected. However, you should keep in mind that these standards are set while taking into consideration what computer games require to run.
Games often require more resources than other programs.
For example, you may not need wavetabled sound. Just remember, what you buy today may be great for running programs today, but bigger and better programs are constantly being developed. What you have today might not run tomorrow's software. Make sure that your system is fairly upgradable. For example, make sure that your processor is upgradable, i.e. make sure that your motherboard has a ZIF socket.