I like to use Makefiles. I like to use Makefiles in Java. I like to use Makefiles in Erlang. I like to use Makefiles in Elixir. And most recently, I like to use Makefiles in Ruby. I think you, too, would like to use Makefiles in your environment, and the engineering community would benefit if more of us used Makefiles, in general.

Smex is a M-x enhancement for Emacs. Built on top of Ido, it provides a convenient interface to your recently and most frequently used commands. And to all the other commands, too.

This mode teaches you to use the proper Emacs movement keys in a
rather harsh manner.

No-easy-keys disables arrow, end, home and delete keys, as well as
their control and meta prefixes. When using any of these keys, you
instead get a message informing you of the proper Emacs shortcut
you should use instead (e.g. pressing down informs you to use C-n).

A preview of the full source code.

A popup window switcher roughly based on superswitcher. This version started off as a clone of simpleswitcher, the version from Sean Pringle. All credit for this great tool should go to him. Rofi developed extra features, like a run-dialog, ssh-launcher and can act as a drop-in dmenu replacement, making it a very versatile tool.

Speedbar is an Emacs Lisp program which allows you to create a special skinny frame with a specialized directory listing in it. This listing will have both directories and filtered files in it. You can then load files into your emacs frame, or expand the files to display all the tags that are in them and jump to those tags. You can also expand multiple directories into your speedbar frame.

Using Shift with the mouse is considered a "power click" which will ignore any cached data that might be related to the navigation desired. When loading a file, a power click will pull that file into a new frame.

For PC users with two button mice, a button1 double click acts as the mouse-2 click most emacs users are familiar with.

Additional keyboard commands are available for friendly file IO functions such as Rename/Copy/Delete, Loading lisp files, and compiling lisp files.
speedbar-multi-2.jpg
Different Modes for Speedbar

Speedbar is more than just file browsing, however. Speedbar is a generalized browser. Speedbar supports:

• multiple tagging methods for files (such as etags, imenu, and semantic)
• multiple major display modes (such as buffer lists, project lists, and EIEIO class browsing,)
• multiple minor display modes that appear when you view special files, such as Info pages, or read mail with RMAIL.