By default, the emacs buffer list appears in a vertical split when you type C-x C-b (or run M-x list-buffers). I use a widescreen monitor which means a horizontal split would be much nicer. Since I couldn't find a Customize setting to change this behavior, I wrote this keyboard macro in my ~/.emacs which does the trick:

(fset 'my-list-buffers
   [?\C-x ?1 ?\C-x ?3 ?\M-x ?l ?i ?s ?t ?- ?b ?u ?f ?f ?e ?r ?s return ?\C-x ?o])

(global-set-key "\C-x\C-b" 'my-list-buffers)