3rd Edition is the culmination and clarification of everything that has made Dungeons and Dragons the most popular roleplaying game in the world. 3E fixed almost everything that was broken in previous editions, versions and variations. No longer is there confusion and interpretation involved in reading the rules. The books are laid out with an artist's touch, every page is full color, and most have action. There are now compelling reasons to be a human.
Gnomes are no longer goofy.
The classes make sense, and any character can multi-class. Any race can be any class. The game uses one mechanic, the d20 system, for almost all of the task resolution. Gone are percentile rolls. Gone are cryptic saving throw charts.