you think so? then, you're wrong buddy..
i own the iMac 3.06 and it is exactly what i need, i work with audio professionally. if you think you are a power pro only with the mac pro, then you just don't know anything about. i use only 1/3 of the cpu power in a whole song/structure. that's enough. and at the same time, i do check my emails/surfing web/using iPhoto/whole iLife suite.
Yes, you can also do audio...
Despite that, the Mac Pro is a much more powerful machine and there is no point for someone changing it for a Prosumer system