Well, I'm seeing a trend that my 13" MBP might be replaced with a MacBook Air in a couple years. So my question is, how many computing devices is efficient for an average person? In another case, for a business guy. Is it efficient to have an iMac, iPad, iPhone, and MacBook Air, plus my company's PC laptop? From where does the point of diminishing utility begin? Should i just have a MacBook Air? Would an external monitor suffice for when i use it at my office table? Is an iPad necessary if you have a MacBook Pro? My iPhone is staying regardless. So, does a combo of a MacBook Air + iPhone seem perfect? What is efficient in your eyes?