HTTPie, an easy to use cURL replacement: https://github.com/jkbr/httpie (disclaimer: I'm the author)

This was a good list for the intermediate command line user looking to customize. For the absolute newbie I'd reduce it down to git/hg, ssh, grep/ack and curl.

For crazy power users, I'm a huge fan of vim+tmux+zsh combo as described in http://www.drbunsen.org/text-triumvirate.html

That's a good list. I considered including Git but that could be an entire article by itself. I've looked at TMux but I just don't I'd use it.

What's the difference between Tmux and iTerm2?

tmux is a CLI terminal multiplexer. As an interactive CLI program, you need a shell to use it. To run such a shell, you need a terminal emulator. iTerm2 is a Mac OS X only GUI terminal emulator.

You can run tmux in iTerm2.

CLI (Mac OS X and Linux): bash, git/tig, svn, cdargs, vifm or ranger (can't decide), vim, grep, man, ssh, a few custom functions and tmux.

GUI (Mac OS X): MacVim, ClipMenu, YummyFTP, Quicksilver, iTerm2, SourceTree, FileMerge, Chrome dev tools.

GUI (Linux): GVim, Glippy, FileZilla, Synapse, Gnome terminal, SmartGit/SmartSVN, Meld, Chrome dev tools.

Terminator (http://www.tenshu.net/p/terminator.html) is a nice replacement for Gnome Terminal thats very similar to iTerm2.

Thanks, I'll take a look.

I don't use any advanced features of iTerm, though, I just use it over Terminal.app because it supports 256 colors. We have not been updated to Lion or Mountain Lion at work so Terminal.app is still limited to 16 colors for me.

zsh, vim, git, pry, ack, htty, pv, multitail to name just a few of the most common and powerful things in my daily text shell arsenal.