Question

I use buffer-menu extensively to switch between buffers. I want to list the buffers which are files or dired. How can I do that?

Answer 1

You can use ibuffer

There you can define your buffer groups. You can mark buffers, use filtering and sorting, do search/replace in marked buffers and other useful stuff.

For your case just put into the hook (ibuffer-filter-by-filename ".")

Here is an example from my .emacs .

(require 'ibuffer)

(setq ibuffer-saved-filter-groups
      (quote (("default"
               ("dired" (mode . dired-mode))
               ("java" (mode . java-mode))
               ("org" (mode . org-mode))
               ("sql" (mode . sql-mode))
               ("xml" (mode . nxml-mode))))))    

(setq ibuffer-show-empty-filter-groups nil)

(add-hook 'ibuffer-mode-hook 
 (lambda () 
  (ibuffer-switch-to-saved-filter-groups "default")
  (ibuffer-filter-by-filename "."))) ;; to show only dired and files buffers

EDIT. If you want to filter out temporary buffers (which name begins with *) you can set the following filter (regex)

(ibuffer-filter-by-name "^[^*]")

It says that the buffer name should start with any character except *.