Fundamental
I use Arch Linux on a Penguin Pro.
I also have a 2007 MacBook which runs Arch Linux. I was surprised that I was able to get the OS installed (I used the guide on the Arch Wiki). I'm waiting for coreboot to support replacing the bios so I can take a shot at really bricking it.
I use xmonad as my window manager and use Dvorak as my default keyboard layout (although the symbols on my keyboard are QWERTY). I've generally had a very good experience with both (although upgrading the haskell compiler ghc is a somewhat annoying process). I also use dmenu to bring up applications in the background. Other than that, I have xmobar set up as a status bar to easily keep an eye on CPU and and network usage.
Applications
I generally use urxvt for the terminal, but also use uxterm
occasionally. I use bash, mostly because it is widely available and so
my startup scripts are easily portable. vim is my editor of choice. I
have set -o vi in my startup scripts to use vim-like keybindings in
the terminal. Additionally, I recently discovered that the line
set editing-mode vi can be added tobe ~/.inputrc to set the editing
mode for all applications built on readline (including python and
gdb).
I use firefox and occasionally lynx for web browsing, thunderbird for email, and newsboat for feeds.
On the occasion that I need to use "office" software such as a word processor or a spreadsheet, I use LibreOffice. vlc generally takes care of my media playback needs. I use Audacity and the Hydrogen drum machine for fun with audio recording. I've had a lot of fun editing photos with the GIMP (GNU Image Manipulation Program).
Appearance
I use unifont and DejaVuSansMono as my console fonts (set in .Xdefaults). My standard color scheme in vim is gruvbox (modified to have a transparent background) and I've also set my prompt and LS_COLORS environment variable with similar colors.
I've set up the XFCE-dusk as the gtk-theme so that everything has a dark look to match with the text environment. I try to maintain this look in applications that I use.
Fun Stuff
By adding fortune -c | cowsay -f tux to my startup scripts, Tux, the
Linux mascot, greets me with a friendly message.
I set the wallpaper in X using hsetroot -full, which is in my
.xinitrc. I have a small script that chooses a random wallpaper from a
directory of images to pass into the program, so that my wallpaper
rotates everytime X is started up. I have transparency set on urxvt to
allow me to see my wallpaper when in the terminal.