Rumors ahead of the WWDC 2012 point towards a massive update of Apple computers.
Apple will hold the WWDC 2012 keynote on June 11. Rumors about a new 15-inch MacBook Pro with Retina Display kicked off an avalance of rumors around updates of Apple computers. The latest rumors point towards Apple updating all computers with Retina displays. This means we will get MacBook Air, MacBook Pro and iMac computers featuring Retina resolution screens as available on the new iPad and iPhone 4S.
Retina Displays are defined by their pixel density. Depending on the screen size, the resolution has to be high enough to get over a threshhold. Apple defines Retina Displays to have a pixel densition above 300dpi.