Retina Display
As a microscopic examination proved in mid-February, the iPad 3 has a 2048x1536 retina display with exactly four times the quality of the iPad 2's display. Checking out a cool graphic on Apple's features website shows you that you actually can tell the difference. The retina display really should change the iPad experience.
5MP iSight Camera
Rumors from NextMedia claimed that the iPad 3 would have an 8MP camera. Though the increase wasn't as dramatic, the video quality is now full HD (1080p, slightly higher quality that the iPad 3's display). And besides, the iPad 2 really needed a camera upgrade, so any upgrade at all is fine.
4G LTE
Here's some great news for frequent travelers; your internet on-the-go has received a substantial boost, as the iPad 3 now supports 4G LTE from AT&T and Verizon. It also supports high-end 3G technologies for the times when 4G isn't available, or you can use the new SIM card slot if neither are available. In addition, the device supports tethering.