As a quick refresher, let's summarize both players' relative strengths. Intel still leads the pack by a noticeable margin in terms of anything related to CPU sales, but that's about it. Despite significantly slower clocking, the Athlon 64 outperforms comparable Pentium models, and also consumes less power - and this applies equally to both single- and dual-core Athlon 64 and Athlon 64 X2 processors. Scientific and professional applications are the exceptions, because Intel's Hyper Threading fits those business niches quite profitably.

In terms of functionality, all the expensive Intel processors in the Pentium D 600 series support the 64-bit extensions called EM64T, which will be important for Windows Vista (due out in Summer 2006 at the latest). Virtually all of them provide support for the Execute Disable Bit (XD) as well. Faster processor models also employ SpeedStep power management technology too; this is found in the Pentium 4 600, Pentium D, and Pentium Extreme Edition series.

The Celeron is available as an alternate choice, which Intel designed as a cheaper processor option for business customers. More interesting are the Pentium 4 and dual-core Pentium D processors (easy to recognize as such; "D" stands for "dual"). The 500 series is equipped with a 1 MB L2 cache; the faster 600 family has 2 MB and supports all the advanced functionality described in the preceding paragraph. The Pentium D is aimed at users who need exceptionally high performance, especially fans of heavy multi-tasking - the simultaneous execution of numerous applications.

Perhaps you've been following these developments for some time now, but it seems that product offerings from the market leader have become so wide and varied that Joe Sixpack might have trouble picking his way through the roster without a program guide. It's also possible that one might be swayed by one or another of the widely discussed deficiencies often attributed to one competitor or the other.