• A completely changed Old World of Azeroth, devastated by floods, earthquakes, and volcanos
• A new profession called Archeology
• Two new races: Goblins for the Horde and Worgen for the Alliance
• New classes available to existing races, like Tauren Paladins and Dwarf Shamans.
• New raids and dungeons, including a Heroic version of Deadmines
• Guild leveling
• Stat changes, like the removal of defense, attack power, and spell power
• A completely revamped talent system

Now, of course, changes to the endgame and an increased level cap mean that you’ll want to get to level 80 as quickly as possible before the expansion comes out – probably in the fall of 2010. Even though there is no release date yet, you don’t want to be caught off guard. You need to get to 80 well ahead of time so that you can start accumulating the gear you’ll need to play the expansion.