Welcome to EverQuest II Answers. What would you like to know?

a large amount.

Currently one of the "quest-a-holics" that I know of has over 5000 done.

here's a great page that shows the achievements for quests.

Edit: There are around 8800-8900 quests as of 3-18-2012, though not all characters can do them all because of class / race / etc. restrictions.