What would you include on a CD/flash drive with Doom stuff on it that contains what you feel are the most important things, without having too much? I've been thinking about it, and I came up with this:
Games
Ultimate Doom
Doom II
Master Levels for Doom II
Final Doom
WADs
Alien Vendetta
Blackgate
ChordG
Classic Episode
Crossing Acheron
Darkening
Darkening 2
Dawn of the Dead
Demonfear
Deus Vult 2
Doom City
Doomsday of UAC
Dwango5
Earth
Equinox
Eternal Doom
Fava Beans
Galaxia
Grove - Alternate
Hell Revealed
Hell Revealed 2
Icarus: Alien Vanguard
Kama Sutra
Memento Mori
Memento Mori 2
Mordeth
Null Space
Nuts
Nuts 2
Nuts 3
Origwad
Phobos
Polygon Base
Requiem
Scythe
Scythe 2
This Suxx
Verada
Void
Vrack2b
Source Ports
Chocolate Doom
PrBoom+
GZDoom
Skulltag
Editing Utilities
DeHackEd
Doom Builder
XWE
Oblige
Patches
SUPRWEP8.DEH
EDIT: I guess Blackgate would be a better choice than The Punisher, seeing as though the latter became a level in Plutonia, albeit a modified version.
EDIT 2: Added Skulltag and Oblige.