Let's see...

Wizardry
Bard's Tale
Hacker
Dream Zone
Uninvited
The original EGA version of Space Quest/King Quest/Police Quest/Leisure Suit Larry rather than the "remastered" versions...
Gal Trader
Taipan
Arcade Boot Camp
Sea Dragon
Miner 2049er
Hades
Spelunker
Lemmings
Iron Storm (Sega Saturn)/any Dai Senryaku games (long shot)

And I seem to remember some weird Sierra-esque Star Trek Adventure Game that had battle sims ala Wing Commander mixed in with other levels

But really, I would die to be able to play a working version of Wizardry/Wizardry IV/Bard's Tale (specifically, IIGS or Amiga version, which had slightly nicer graphics)...

I noticed someone earlier mentioned Dungeon Siege and would like to add my vote for that also.

In addition

1. Dungeon Siege + LOA
2. Dungeon Siege II + expansion.

Pretty please.

Holy Necromany.

Still, it's probably better than making YET ANOTHER &@%!ing thread about "what gay-ms U want?!"

Also : lol at some of the posts on 1st page. Should be happy they're available here now! ^_^

Going to update my list since some have came out or coming out:

system shock 1
starlancer
freelancer
Grim Fandango
All total war games
No one lives forever series
Blade Runner (both pc games)
Mechwarrior series
Shadow of Destiny
Star Trek Bridge Commander
Star Trek Armada 1 + 2
Warhammer Dawn of War 1 with all expansions.

Age of mythology + exp (coming to steam, probably on gog too)

Dang, I just realized my list has gotten WAY smaller, added a few new ones. Keep up the great work guys!

Year Walk:
http://simogo.com/work/year-walk-pc/

http://www.gog.com/wishlist/games/year_walk

It looks very interesting and it's already available DRM-free elsewhere.

FINALLY remembered those old dos space colony game I used to play when I was a teen. Been trying to remember forever. It was outpost and outpost 2 by sierra. Fun games, would love to see them on gog!

system shock 1
starlancer
freelancer
Grim Fandango
All total war games
No one lives forever series
Blade Runner (both pc games)
Mechwarrior series
Shadow of Destiny
Star Trek Bridge Commander
Star Trek Armada 1 + 2
Warhammer Dawn of War 1 with all expansions.
Homeworld Series
Outpost 1 + 2 by sierra.