Now, the GPU is inconsequential if all you do are tasks like e-mailing, light Web surfing, and preparing documents in Word and Excel. But in some cases, the GPU makes a big difference. 3D video games are a given, but intensive graphics are creeping into many other applications. Google Earth, for example, now provides 3D views of urban landscapes, and my poor iMac nearly overheated trying to render a view of downtown Manhattan. A little less power-intensive, but maybe even more fun, is PicLens—a web browser plug-in that lets you navigate photo sites like Flickr or Google's image search in 3D, similar to how you flip though album covers in iTunes.