Return Fire
F-22 Lightning II
Prince of Persia(original)

Any of the Zork games that are not already free such as:
Return to Zork
Zork Nemesis
Zork Grand Inquisitor
Zork: The Undiscovered Underground

Missionforce Cyberstorm (the first one!)
Great Naval Battles Series
Wargame Construction Set 3 - Age of Rifles

I know it's probably been said more than once, but I would do anything you ask if you bring Crusader: No Remorse and Crusader: No Regret to GOG
Wing Commander would be neat too
Also, those old SCUMM games would be great especially Sam & Max

Freedom Force
Tie Fighter
Dungeon Keeper
All the infinity engine games
System Shocks
Heroes of Might and Magic 2-4
Wizardry
Master of Orion 2
Master of Magic
Jedi Knight 2
Ultima Underworld games.

Megarace!

One more, since all the Fallout games are already on here...
Wasteland. Never played it but would love the opportunity.

I'd like to see also:
Warcraft 1 & 2 with exp
Cyberia 1 & 2
Heretic 1 & 2
Medal of Honor series
Syndicate Series
Star wars: Rebel assault

I don't know if anybody has said this before but for my 2c I'd like to see The Longest Journey and some other adventure games.
They get far too little appreciation in today's games market.

This one has probably been posted already but I'd love to see The Elder Scrolls: Arena and Daggerfall as well.

I would really like to see ''Dark Colony'' from '' Strategic Simulations, Inc''. and published by ''GameTek''
And the expansion ''Dark Colony: The Council Wars'' developed by ''Sold-Out Software'', and published by ''GameTek''
Dark Colony

Hi
It would be great if you can get
Kingdom O Magic by GT Interactive
Noctroplis by EA
Thanks.

Planet's Edge
Master of orion 2
Master of Magic
Deus Ex

Panzer General 2
Tie Fighter (CD version w/ music)
X-wing (CD version)
Wing commander series
Delta force series (excluding land warrior)
Warcraft 1
Master of Orion
Dark Forces
Hexen
Rise of the Triad
Syndicate series
Interstate 76
Heroes of might and magic series
XCom series
Road Rash (yes i said it )
Betrayal at Krondor (maybe w/ a little face lift)
Doom series
Quake 1
Shadow Warrior
Well thats about it for now, ill try to get the cobwebs out of my brain cleaned out and remember more games, but this is pretty much what most people here recall...

Another vote for the classic Sierra and LucasArts adventure games.
Another World (aka Out of This World) and the "sequels" (don't recall their names)
I'm also a rally game fan, so:
The whole Colin McRae Rally series
Rally Trophy
Rally Championship 2000 (aka Mobil 1 British Rally Championship)
Richard Burns Rally