LostCircuits has an informative article on-line today that focuses on a number of popular audio and video encoding applications. They pit a handful of Intel processors against similarly priced counterparts from AMD. If encoding performance is important to you, this article will likely be of interest.
"Arguably, the biggest factor driving the computer industry is gaming. However, the home entertainment sector, especially encoding of audiovisual content, is becoming increasingly important as well. Ripping and editing software ranges from super-expensive studio editions to free downloads. Each program has its own quirks, favoring either Intel's or AMD's processors. We took LAME, Dr. DiVX, NeroVision4 and Monkey's Audio as representatives of the inexpensive (or free software) and ran AMD's dual core CPUs as well as Intel's Core2 Duos through the paces. One issue to keep in mind is that not all programs are multithreaded, this is particularly true for audio stream-encoding, however, multiple cores can take care of multiple audio streams in parallel. "