I would like to see minecraft implement the option to change your name. It wouldn't be your account name, it could add a "character name" field. For those who already have an account, it would remain the same until you changed it. I would very much like to see this change implemented In the near future, and I think it would make a great addition, especially to RPG servers.
is your in-game name. (the one which other players see above your head)
No thanks, it'd get too hard to tell who's who. Someone may be Jack1234 one day, and then Nickolas55 the next.
Also, I think what Notch should do is offer a name change for say...$5.
Maybe if you bought during Alpha, you get one free name change.