Acually the whole game, its hard to pin point one thing here. I really like a healthy mix of PvE and PvP so looking forward to exploring the world with the 3 different factions, which also will make it like 3 different games/stories in one. checking out all the dungeons and crafting everything I can (hopefully they have a nice crafting system in place).
Then there is the 3 faction PvP, which I havent really had great fun with since DAoC. GW2 was kind of disappointing with their take on it with the WvW and I'am waiting to see if Matt Firor & team can do it right again with the awesome world of Elder Scrolls around it.