Use ido (nearly) everywhere.
M-x package-install [RET] ido-ubiquitous [RET]
If you use the excellent `ido-mode' for efficient completion of file names and buffers, you might wonder if you can get ido-style completion everywhere else too. Well, that's what this package does! ido-ubiquitous is here to enable ido-style completion for (almost) every function that uses the standard completion function `completing-read'. License: This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Emacs; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.