My 2008 Unibody 13" Macbook is dying a slow painful death as far as specs are concerned. It struggles with multiple applications and hates Photoshop. Plus I can't get software updates anymore because I'm still running Snow Leopard. I refuse to update the OS and give the already strained system more to handle. However, given it's lasted 4 years it has served me well for 4 times as long as any other laptop I've ever owned.
I'm in the market for a new Mac and the 13" rMBP looks like the computer for me. To be honest as long as it has a retina screen, 8GB of RAM, and can run CS6, the new Sim City game coming next year, and Starcraft 2 it will be good enough to last me another 2-3 years.