Favorite Linux Applications: What is yours?

A List of my favorite Linux applications by category. What is yours?

0. Distro specifics (simply because some of the tools are not
available or useful on all distros)
0.1 Current favorite distro (and reason - what do you want in a distro?)
Mepis (KDE-based, Debian based, User-friendly, Fast install, good
balance between stability and up-to-date applications, familiar to me
:-) )
0.2. Favorite Desktop Environment
0.2.1. Heavy (If you have the Graphics)
KDE (Don't ask me why... just personal taste - eye candy?)
0.2.2. Light (Older computers etc.)
Fluxbox (Fast)
LXDE (Only discovered it recently - so far I'm impressed)
[I also get tired of one specific Desktop Environment easily, so tend
to install more than one and switch between them or even run more than
one simultaneously - one for work and one for play]

1. Daily must-haves: Tools / utilities that you use everyday.
Indispensable on your computer and one of the first applications you
would install on a new computer if it was not already there as part of
your base distro:
1.1 CLI tools:
Aptitude (package manager)
mc (Midnight Commander)
gpm (console mouse daemon)
fbi (Frame-buffer image viewer)
screen (Console Screen Manager)
1.2. GUI tools:
Yakuake (Teminal emulator: hide/show with shortcut key)
SciTE (Text Editor)
GIMP (Graphics Program)

2. Indispensible tools / utilities that you only use once in a while,
but still consider as a must-have:
2.1 CLI:
cfdisk (CLI disk partition)
elinks (Web Browser)
2.2 GUI:
gparted (GUI Disk partition tool)
wine (Windows "emulator")
VM Virtualbox / VMWare Player (Virtual Machines)
k3b (Burn DVD's & CD's)
VLC (Multimedia player)

3. Office applications (Indispensible office-type applications)
3.1 CLI:
?
3.2 GUI:
LyX (Document Processor)
Gnumeric (Spreadsheet - faster than LibreOffice/Open Office)
Abiword (Word Processor - faster than LibreOffice/Open Office)
LibreOffice / Open Office (Only way to read some Miscrosoft formats)

4. Specialist Tools / Applications that you use regularly and consider
as a personal must-have, but that will only be useful for users with
specific interests or jobs
4.1 CLI
GRASS (GIS - also with GUI)
weex ("Automatic" ftp website updater - CLI)
nmap (Network scanner)
4.2 GUI
Quantum GIS (GIS)
Lazarus (Free Pascal IDE & GUI builder)
Boa Constructor (Python GUI IDE)
Eclipse (Java IDE)
KDevelop (C++ IDE)
Bluefish Editor (Web Editor)
BibleTime (Bible Study tool - uses e-sword document format)
MuseScore & NoteEdit (Music Score Editors)
Audacity (Sound Editor)