1. Lucy Ricardo & Ethel Mertz
Show: 'I Love Lucy' (1951-57)
Stars: Lucille Ball and Vivian Vance

Friend-ly conversation: They fought, they made up. They schemed, they got caught. But TV's first truly great BFFs remain the standard by which female friendships in TV comedies should be measured, especially for Ball and Vance's skills with some of 'I Love Lucy's' physical comedy scenes, from the famous chocolate factory conveyor belt in 'Job Switching' to their attempts to fool a friend (without her glasses) into thinking Lucy was a famous Marx brother in 'Lucy and Harpo Marx.'

That's what friends are for: Many of Lucy's schemes revolve around her trying to become part of hubby Ricky's showbiz biz, despite any discernible talent. But Lucy's lack of song-and-dance skills aside, her performance with Ethel on 'Friendship,' the Cole Porter tune from the musical and movie 'Du Barry Was a Lady' (in which Lucille Ball starred with Red Skelton and Gene Kelly), epitomizes how fun their friendship was.


http://www.tvsquad.com/2010/07/26/memorable-tv-best-friends-no-10-1/

It's very hard to argue with Lucy and Ethel being TV's best best friends. I think you can also say that Ethel Mertz was TV's most loyal friend!