I adore the Retina Display. Compared to the Droid (and Droid 2) and the Galaxy S, the Retina Display offers the best overall package of resolution, image quality, brightness, outdoor usability, and resolution.
However, it's not just that the Retina Display is so amazing, but that previous generation iPhone displays are horrible. By the time that the 3G came out, it already had an outdated display, and it was unforgivable for Apple to release the 3GS with THAT LCD.