Well AMD's new 940 pin socket AM2 cpu's and DDR2 ram will be out in a few months, plus new motherboards for them.
The cliche line is to not wait because there'll always be something better on the horizon.
As for me, I'm waiting a while for that stuff to be out on the market and debugged a little bit until building my next rig, maybe till early 2007.
Experience: I bought an Athlon Winchester core cpu about a week before they were obsoleted & replaced by faster, cooler. lower power Venice core models, because of that "don't wait there'll always be something better on the horizon" advice I bought from someone else. GGrrrrr gnash gnash arrgh