There are alot of servers and all of them are different. Once you have the game running, you can log into the login server and you will see a server list of all of the servers. You can easily see from there exactly which servers have the highest player numbers. Pretty much any server with more than 10 characters on it is probably worth checking out.
Here is a small list of some (but not all) of the popular ones.
http://www.eqemulator.net/forums/showthread.php?t=24875