An interesting article has just been published by PC Gamer: http://www.pcgamer.com/what-games-would-you-put-on-a-classic-pc/

Inspired by the upcoming Super NES Classic Edition, they created an hypothetical Classic PC, filling it with 21 classic games: obviously many titles are Good Old Games™.

PC Gamer's Classic PC games list:

01) Civilization II (Microprose, 1996)
02) Commander Keen (id Software, 1990)
03) Day of the Tentacle (LucasArts, 1993)
04) DOOM (id Software, 1993)
05) Duke Nukem 3D (3D Realms, 1996)
06) Lemmings (DMA Design, 1991)
07) Monkey Island 2: LeChuck's Revenge (LucasArts, 1991)
08) Myst (Cyan Worlds, 1993)
09) Prince of Persia (Brøderbund, 1989)
10) SimCity 2000 (Maxis, 1993)
11) Star Control II (Toys for Bob, 1992)
12) Star Wars: Dark Forces (LucasArts, 1995)
13) Star Wars: TIE Fighter (LucasArts, 1994)
14) System Shock (Looking Glass, 1994)
15) The Oregon Trail (MECC, 1990)
16) UFO: Enemy Unknown (Mythos Games/MicroProse, 1994)
17) Ultima Underworld: The Stygian Abyss (Looking Glass, 1992)
18) Ultima VI: The False Prophet (Origin Systems, 1990)
19) Warcraft II: Tides of Darkness (Blizzard Entertainment, 1995)
20) Wasteland (Interplay, 1988)
21) Wing Commander III: Heart of the Tiger (Origin Systems, 1994)

So, which is your list?

I would just install a driver to plug in my 20tb raid drive and then play some games rather than waste time trying to rank everything.

Mecharior 2 and expansions
Unreal Gold (even though I already own it from here)
Quake 1 and 2
Heavy Gear 1 and 2
Battlezone 1 and 2

Ditto. Set up the machine for network access, and just access the file server in whatever obscure way is possible.

The great thing about a PC is that I don't need anyone to release a "classic PC" and I don't need to limit myself to 21 games. I can just play all of them. And if the mood ever struck me, I could also emulate all the old Nintendo stuff too.

Pretty good list. Personally I would take out Wasteland for Crusader: No Remorse. Also System Shock is great but not really one that I feel has replay value.

My list would be:

1. Strife
2. Bio Menace
3. Flashback: Quest For Identity
4. Little Big Adventure
5. Wing Commander: Privateer
6. Crusader: No Remorse
7. Death Rally
8. Star Wars: Dark Forces
9. Major Stryker
10. Normality
11. Realms of Chaos
12. Centurion: Defender of Rome
13. Alone in the Dark
14. X-Com: UFO Defense
15. Wacky Wheels
16. Raptor
17. Master of Orion
18. Sid Meier's Colonization
19. Terminator: SkyNET
20. Crusader: No Regret
21. Blake Stone: Aliens of Gold

I went with games that came out no later than 1996. There's still plenty of DOS games in my GOG library I haven't gotten around to yet, some I can imagine would knock some of the other titles out of that list.
I have toyed with the idea of making a dedicated computer for older games, potentially something like an arcade cabinet, or a cockpit setup dedicated to playing simulator games.

1. Windows 10

I'd buy that for a dollar.

Let's see...
1. Cathode-ray tube amusement device.
2. Bertie the Brain
3. Tennis For Two
4. Spacewar (1962)
5. Lunar Lander (1969)

You know, really historic stuff. Everything else I can just use a regular PC for, so why would I need a portable device/

I love the lists so far, but can't help but feel like one of the Command & Conquer games needs to be on them. Maybe go for Red Alert 2 so you have the weird as well as the classic controls.

My list of 20 games to put on a "Classic PC" based on what I have played in the past and really liked: (in no particular order). All games are pre-2000 (games like Red Alert 2 or Diablo 2 are just too recent to be called "Classic" IMO, good though they are)
1.Ultimate DOOM
2.Command & Conquer Tiberian Dawn for Windows 95 (with the Covert Ops expansion pack and the official N64 and PSX maps that are out there)
3.Sim City 2000 Special Edition
4.Space Quest 1 EGA (the MT-32 sound track in the VGA remake may be better but the original with all the typing is more "classic" for me than the point-and-click of the remake)
5.Day of the Tentacle
6.Diablo + Hellfire Expansion
7.Star Control 2
8.Transport Tycoon Deluxe
9.Sentinel Worlds Future Magic
10.The Incredible Machine 3 (just because it has more pieces and puzzles than the first games in the series)
11.The Bard's Tale (the original, not the various remakes)
12.Captain Comic
13.System Shock
14.Myst
15.Contraption Zack
16.Heroes of Might and Magic 2 Gold
17.Rollercoaster Tycoon Deluxe (just qualifies under the "only games before 2000 rule" even though the expansions didn't come out until 2000"
18.Scorched Earth
19.Duck Tales Quest For Gold
20.Strife (no, not the online game, the old Doom-engine RPG-ish game)

Just adding some to the classics already mentioned, though I would limit to dos games only.

X-COM: Enemy Unknown
Raptor: Call of the Shadows
D/Generation
Stunts
Mass Destruction
Falcon 3.0
X-Wing
Chuck Yeager's Aircombat
Geoff Crammond's Grand Prix
EF 2000
NASCAR Racing
Jagged Alliance
Indycar Racing
Red Baron
Tornado
One Must Fall 2097
TFX
Sensible Soccer
Secret Weapons of the Luftwaffe
Commanche: Maximum Overkill
Aces of the Deep
Pinball Fantasies
Syndicate
Populous II
Destruction Derby
Assault Rigs
Settlers II
Archimedean Dynasty
Carmageddon
Wing Commander: Privateer
Lands of Lore
Terra Nova
Earthsiege
Wetlands
Terminal Velocity
Ecstatica
Flashback
Aladdin
Descent II
Panzer General
Tomb Raider