no the 64 is not just a gamer computer. a lot of people are using it for large track and plug in counts in recording studios.
i would suggest you read a bit about it, by searching using the bbs search ,
and plug in the search amd 64. a number of configs will come up.
if you tell us all what you want in terms of track counts, plug ins, and how many tracks you wish to record concurrently....it would help make suggestions. right now the amd 64 is the king of the hill. unless you go dual amd opterons. do some pst researching at nuendo.com as well.
then once you become familiar ask q's.peace.