Hello all, I am getting ready to buy my first Mac, a new iBook. I have also convinced my girlfriend to switch and she is leaning toward an iMac top of the line. What are the performance limits to the consumer machine? She will be using Autocad some for design and architecture projects, but no other really intense software. She has $2100 and can get ADC discount. Would you suggest the iMac or should we be looking at a PowerBook or Tower?