If you think the G5 is fast now, wait a month or two. According to some rumors, models up to 2.6 GHZ should be released soon. (2.2, 2.4, and 2.6 GHZ models were mentioned).
http://www.macrumors.com/pages/2003/12/20031204180906.shtml
Steve Jobs has also promised a 3 GHZ model by this summer.
For those keeping score, Intel is claiming to be able to hit 4 GHZ sometime next year with their 32-bit Pentiums.
AMD actually shares tech with IBM, so the IBM 'G5' and AMD's Opteron chip should be keeping roughly equal pace.
