Guildwars GOTY Edition?

So, I just picked up Guildwars GOTY edition for $5 at Target. The box tells me little about what the difference is between this and the vanilla version. Amazon's description doesn't help either. What am I getting in this version of the game and is it still a solid play w/o expansions? Don't know anything about the series but the title to give you an idea of where I am coming from and how noob I am to this series.

Thanks!