Well, I never thought I would hit that limit. I guess I haven't really hit it personaly but my son has.
He likes creating characters, leveling them to 3-4 and then moving on to a new server. He has whole servers filled up with various similarly named characters. They rarely make it above level 5 and never leave the starting areas (He's only 6 himself).
I have since learned that you can have a maximum of 50 characters across all servers. I have 10 on my main server and the rest are all his "alts".
He does have a NE Hunter on my main server that has made it to 24 with a little help from Dad. Now that he can get a mount at level 30 I feel the need to help him out just a little more.