Outcast with Sacrifice and Giants tied in 2nd

Hard choice. So many good games on here.

Probably... Unreal? Either Unreal, Painkiller, Machinarium, or Miasmata, I think. Oh, but then there's also Deus Ex. And FTL.

Hmm...

Arcanum. It is the only GOG game I've owned that I played all the way through and enjoyed every moment of it. Giants: Citizen Kabuto might come in second, but I was really disappointed with the Kabuto campaign. It was fun for a little while, but then it just got boring.

IL-2 right now. But I have a few in my catalog right now that will be strong competitors. I just need to play them.

I really enjoyed Thief: DS, give a shot, I'm sure there are many things you will like about it (even if there are some that you might not)

Can't pick just one. But of the GOG games I've played through so far, in my top list would be:

Planescape:Torment (for the story)
Icewind Dale (I love the IE games, but this is the one I keep coming back to over and over. In the last 2 years I've played through it at least 2 dozen times).
Neverwinter Nights (A bit of a 'cheat', as I've not really played my GOG version - i.e. not used the game keys on-line yet - but I played this game almost exclusively for a stretch of about 3 years. Sunk hundreds and hundreds of hours into it)
The Witcher (Yeah, the first one. One of the few games I finished and then immediately went back through a second time)

Freespace 2.

Although it certainly isn't an easy choice. Freespace 2 emerged victorious in this competition after exiting a steel cage deathmatch with the likes of Neverwinter Nights, Wing Commander, Alpha Centauri, Tyrian 2000 and Empire Earth. It also had to deal with new challengers FTL, Botanicula, Symphony, To the Moon, and Resonance.

What I'm trying to say is that GOG takes the "Good" part of its name extremely seriously, while nodding to the previous "Old" part of the name and definitely sticking with the "Game" part. GOG shows us some of the best games of the past, present, and (with pre-orders like the one I made with Symphony) future.

Probably Duke Nukem 3D. I'd say 70% because of nostalgia though.

Counting games I've actually bought here, I've played Symphony the most, so that would be it so far.

Counting games released on here that I owned before, it would be a toss up between Duke Nukem 3d and Unreal Tournament. I poured many many hours into both of them.

Sorry LOL :P

It is so hard to pick just one given GOG's large library of great classics. I've bought over 100 "favorites" at this point!

I know, I will pick one game and one series even though there is many more I regard very highly in my bookshelves.

Baldur's Gate & Tales of the Sword Coast. I just loved this from start to finish, everything about it. From all I've heard I may like BG 2 even more when I get to it as well as Planescape Torment. The Infinity Engine games were my first purchases here. I came to GOG for those and have stayed for all the other goodness I became aware of after that.

It is a good thing I found GOG because they were able to get for us a series of role playing games that are very, very special to me: the Ultima games! More than any other game up to its time, Ultima 7 The Black Gate taught me just how engrossing and immersive and fun gaming can be in general and RPG games in particular. When I experienced Ultima 7 The Black Gate from start to finish, I became a gamer. That was when it happened, right then and there. The rest is history as they say. :D

So far:

Wing Commander 1 + 2
Privateer
Quest for Glory Series

Overall I'd have to go with HoMM3 (with Alpha Centauri a close second). If I limit it to games that I hadn't played before I got them on GOG then it would be Gothic 2.