Installing OS X Lion on a 3 1/2-year old MacBook Pro made it clearer than ever just how slow my old machine had become. Beachballs left and right, UI lag, incredibly long reboot times, dismal application load times as someone accustomed to the "instant on" feel of an iPad or iPhone, I was starting to hate my Mac, even though I liked Lion.
Playing around with a new MacBook Air in the shops brought back that feeling of "click it and it happens" to OS X, but I found myself unable to affor
