Duncan Davidson posted this awesome post on his blog demonstrating how powerful the retina display is. Hop over via the link to check out his demo. The display is capable of showing all the finite details in such high resolution that takes one breath away. However, be warned that Safari will downsample all pics to 1024 x 768 the most for most JPEG files 9apart from progressive JPEGs). PNG files were told to be ok. For more info on how Safari down samples pics, check out this article, Safari Downsamples Your Images, No HD, from Andrew Ku and Alan Dang over at Tom’s Hardware.
Another great thing about the retina display is that when you load up an iPhone app on your new iPad even in double size due to the higher resolution. Check out this short video below on more details.