Planescape Torment*
Fallout*
Commandos 2
Psychonauts*
Soul Reaver*


*Finished for the first time this year

1. The Longest Journey
2. The Witcher
3. Baldur's Gate 2
4. Planescape Torment
5. Fallout

hm.. it's hard to say.. too many epic games..
i guess it would be something like..

1. Ultima 7
2. Planescape Torment
3. Anachronox
4. Heroes of Might & Magic III
5. Sid Meier's Alpha Centauri

honorable mentions: Gabriel Knight, Might & Magic VI, Fallout, Gothic 2, The Witcher, Arcanum, Betrayal at Krondor.

Updated list:

1. Heroes of Might & Magic III
2. Planescape: Torment
3. Fallout series
4. Blood
5. Age of Wonders: Shadow Magic

Honorable mentions(aside from my original list): Battle Isle Platinum, Gabriel Knight: Sins of the Fathers, Rollercoaster Tycoon 2, Shadow Warrior, Space Rangers 2, The Longest Journey

Here's my list. All are some of my favorite games, but I also chose some that have been hard to find in the past and so I have to give GOG extra credit for providing them.

1. Wing Commander 3,4
2. Crusader No Remorse, Regret
3. Bioforge (Yep I love Origin)
4. I76
5. Total Annihilation

I've thought of checking that game out. Curious, is it an old favorite for you or played recently?

I can't pick just 5, so:

1.) All the Infinity Engine RPGs
2.) All the Sierra adventures
3.) All the Ultima games
4.) All the Might and Magic games (including Heroes games)
5.) All the Wing Commander games

There! That's five and even that is incomplete.

In no particular order:
-Duke Nukem 3d.
-Shadow Warrior.
-Fallout.
-Moto Racer.
-Rollercoaster Tycoon.

If it's okay, I'll bump this if at least a couple people post, and it ends up getting lost again. (back in the 3rd or 4th page, I assume)

This isn't the exact order and almost all bought back in the day, but:

Duke Nukem 3d
Deus Ex
Unreal Tournament
Street Fighter Alpha 2
Descent

Since a couple people did an indies/modern section also:
Torchlight
Trine
La Mulana
Hotline Miami
FTL

Yup.
And my top 5 games are
5. unreal tournament 99
4. ut2004
3. rct 2
2. rct 3
1.ROTT 2013!

Fallout's
Gothics
Europa 1400 The Guild
Jagged Alliance 2
Arx Fatalis / Silent Storm (really couldn't decide)

Bard's Tale
The Witcher
Neverwinter Nights Diamond
Stronghold HD
Dungeon Keeper

Witcher
Witcher 2
FarCry
Divine Divinity
Amnesia