I was thinking of converting to and buying a top of the line iMac when they are updated with the penryn chips. However I am concerned about the iMac's longevity as I keep my computers about 5-6 years. I don't mean in terms of the parts breaking down but being able to handle the next OS X 10.6 and other applications down the line. Should I just buy the recently updated MP and be done with it? Or will the iMac last that long? I not concerned about the high price of the MP. I know the MP will be overkill and a half, but I just don't want to be forced to update HW early. Also where would be the best place to buy RAM if I'm in Australia?