Basically, trying to figure out if it's better to buy and keep a Mac Pro longer or to buy an iMac and replace more often. My guess/opinion is that a Mac Pro lasts about 6 years before slowing down and showing signs of being obsolete while it's every 3 years for an iMac. Do you agree, what's your opinion? iMac 24" costs about $2000, so in 6 years the cost is $4000 Mac Pro cost about $3300. But to complicate matters for the next 6 years I could keep the back-lit LED monitor and just buy a new Mac Pro tower which would be at today's prices $2500 for another 6 years. But for the next 6 years the iMac would be another 2 * $2000 = $4000.