Don’t kill-buffer, kill-this-buffer instead

Here’s a tiny tip. By default C-x k runs the command kill-buffer which prompts you for which buffer you want to kill, defaulting to the current active buffer. I don’t know about you, but I rarely want to kill a different buffer than the one I am looking at, so I rebind C-x k to kill-this-buffer which just kills the current buffer without prompting (unless there are unsaved changes).

Just add this to your emacs config file 

(global-set-key (kbd "C-x k") 'kill-this-buffer)

Update 2017-04-24

Commenter thbit points out that using kill-this-buffer in this way is unstable (see discussion here). Here is a safer alternative. 

(defun bjm/kill-this-buffer ()
  "Kill the current buffer."
  (interactive)
  (kill-buffer (current-buffer)))

(global-set-key (kbd "C-x k") 'bjm/kill-this-buffer)