Compy is a player with impeccable manners, no lip, no whine and you can close the browser on it without fear of a public "outing" for poor sportsmanship!
I think more levels would be good idea... one between EASY and MEDIUM and one between MEDIUM and HARD.
Bring back Compy! 
I enjoy losing to the easy and medium computer several times. I have yet to play the hard one. It would be a good idea to bring them back. I learned a lot about my blunders by playing them.
The Computers have been temporarily removed from the Live Chess but we hope to have them back soon. The recent State of Chess.com broadcast on ChessTV was asking about the Play Against the Computer feature (http://www.chess.com/play/computer.html)
I noticed the Live Chess Computer is gone again, and during the recent ChessTV
broadcast it was asked how many people used it and not many answered.
Will it return again, I really enjoy playing the computer?