I wonder how rgustafs is feeling at this point... question answered or more confused than before?
Maybe give the new designer a budget and let him/her decide what they prefer to do with it.
Agree. With all our minutia hubbub. How much do you have to spend? Do you have to worry about color in the workflow? I have truly professional design houses that do nothing with profiling. They just use Apple default in Cinema displays and iMac. They never have problems with printers etc... Or if they do they never mention it. If you have the budget get a 6-core Mac Pro. If not, get the "all in one with usable and pretty great display" iMac.