Like fangbite wrote in my other thread, I think it is good, if we could make a list, what game from GOG works good/ not so good with Ubuntu/Linux and Wine.
I will edit this post with alle tested games. :)
I take the start:
Games with Wine tested:
Descent 3
Fallout
No Problems with the installation, starting the game also worked without any problems.
Fallout 2
No Problems with the installation, starting the game also worked without any problems.
Freespace
Giants: CItizen Kabuto
Hostile Waters: Antaeus Rising
Kingpin
M.A.X.
M.A.X. 2
MDK 1
Original War
Perimeter
Sacrifice
Stonekeep

Well, solutions like Wine arent 100% effective, there are many errors and glitches for each individual case, so GOG couldnt advertise proper linux/mac support, only probably "go to the community boards if you want linux/mac support".

Yeah, I guess that was more the case that I was leaning towards. I just think GOG or its users shouldn't be afraid to do what they can to help out those willing to actually purchase these games. Just make it apparent that Linux users are welcome.

The fact that this thread exists goes a long way towards establishing that already. Just to expand on the idea that Linux is welcome, I'm kind of the resident Wine "expert" on the Ubuntu forums, so if anyone needs specific help with Wine, I can try to help out. I'm no where near as fluent in DOSBox or ScummVM, however.

I agree, of course, in my case, Im trying to help out the most i can to get other GOG users play their favorite games on Linux, specially the older DOS based ones. Specially ROTT, since it's one of my favorite games too. But this support is gonna be unofficial.

Stronghold - How to share Savegames with Windows
If you're like me and use two Operating systems, you like to switch between the two. I play Stronghold on both Windows and Ubuntu and I got bored of copying save files over.
So, it is actually possible to share savegames between Windows and Linux.
Downside is you need to mount your Windows everytime you want to play Stronghold, or add an entry into fstab or something. Anyway, open up winecfg (either from Terminal or the Wine section on the menu) and "Add Application". Locate stronghold.exe.
Set it to Windows XP or something else. Now go to the Desktop Integration section, change "My Documents" (currently set to your Home) to the My Documents on the Windows partition ( On XP this is /media/[WINDOWSDISK]/Documents and Settings/You/Documents - replace [WINDOWSDISK] with the mountpoint of the Windows disk).
Now you're savegames on Stronghold will share the savegames from Windows, as well as the options etc.

Be careful about pointing Wine at an actual Windows installation. For sharing simple files like save games, its not a big deal, but for some things, Wine can wreak havoc with your Windows install, making it completely unusable.

I do have doubts that writing savegames could do any damage.

Like I said, sharing simple files like save games is not a big deal. Just don't get the idea that because that was harmless that doing anything more will not be harmless.

Anyone else tried Capitalism Plus under Linux + DOSbox? It seems to have a strange bug where the company goes bankrupt after a few seconds/minutes. Link to topic.
This is what I did, short version:
-Install and try to run the game under VirtualBox => very slow, with some heavy unresponsiveness (plus no "stretched" fullscreen);
-Get the files and run the game using the native DOSbox version under Linux => game has that weird bug;
More details on the other thread. Thanks

Duke Nukem: Manhattan Project installs and runs flawlessly (with one exception explained below) using either the OpenGL or Direct3D renderer. I even have gamepad support with a Logitech Dual Action gamepad.
The only problem I've encountered is that if you die in the first boss fight, the game crashes, but this is a problem with the game in general and is being discussed in the following thread:
http://www.gog.com/en/forum/duke_nukem_series/prism3d_error/_/last
The workaround for now is to open the console by pressing ~ (the key left of the 1) and type the command:
map e02p01_a01
This will take you to the beginning of the second episode.

I just found this thread, and I'll try to add my experience with gog games and linux.
General consideration:
- gog should make this post (or a similar one) a sticky thread so it is easy to find, and add what support they could (even if merely moral) to it...
- i have recently changed laptop and distro version and maybe not all the test were made on this but eventually they should :) i have an hp pavilion dv5-1120el with FC10
- i usually try any program first in cedega for the ease and cleanlyness of disinstallation, if it does not function well (or att all) i try with the stock wine, that some time give much better results, in both cases i'm not too adepth and does not expend too much time fiddling with the options, so maybe sometink that dosn't function for me could function with some tweak.
- the gog installer had some glitches but in the end always work both in cedega that in wine.
- if the game is for dos i usually install via gog installer, take the gamefiles and use them in dosbox (or scummvm if it's the case)
- used every game only in single player, never tested multiplayer or map editor if present.
- linux only here, so no windos comparison having none...
lure of the temptress
work fine in scummvm
simon the sorcerer
work well with scummvm
duke nukem 3D
work smootly in dosbox, after configuring the soundcard
descent I e II
work fine in dosbox but much better if you use the game data with some of the project that reimplemented the engine with opengl see:
- http://d1x.warpcore.org/
- http://icculus.org/d2x/
- http://www.descent2.de/d2x.html
- http://www.dxx-rebirth.de/
don't remember exactly what's the one i used, maybe the last one.
ghost master
i were unable to use it fullscreen, it doesn't take well the 16/10 screen of my laptop and put part of the game out of the screen...
but in desktop mode 1024/768 work very well.
sacrifice
work flawlessly
giants citizen kabuto
i had some problem initially, it doesn't function well on cedega (don't remember wy) so use wine, here it function, but it crawled even in the menus, untill i changed the video driver to one that funcition.
now it work flawlessly.
freespace
don't remember very well how, but initially it doesn't play well.
now in wine it is ok. you need to launch FreeSpace.exe to config it.
there is still a problem with all the text, it is confused a little but still readable.
gameplaying wise the mouse is barely unusable for the flying (much worst than with the old x-wing)
finally the sore points:
MDK
great game and great delusion! i was completely unable to play it :(
the purely software mode doesn't display anyting (maybe because it try to use 8bit color that cannot dinamically be changed?)
the d3d mode work great... except that kurt and the other animation doesn't appear on screen...
likely there could be ways to make it work, but i do not know how and have not enough energy to try again... :(

So far, Jagged Alliance 2 works fine with wine, no bugs encountered. Haven't played it through, though.
It would be nice to see test results for certain games run directly with DOSbox or ScummVM, without wine. Here's my list:
Stonekeep, Cannon Fodder and MAX runs flawlessly under DOSbox.
Broken Sword 2, Beneath a Steel Sky and Lure of the Temptress works fine with SummVM.
All games were played on Slackware 12.2 with wine 1.1.14, dosbox 0.72 and ScummVM 0.12.0

so far I tested Fall out 2 and it worked. I just bought Alien Nations will see what happens

DOSBox and ScummVM are cross-platform; compatibility is identical no matter what OS you run them on.

I've just tried out Painkiller: Black Edition.
I'm running Slackware 12.2 and Wine 1.1.18.
It works pretty much flawless. Installed directly from the installer with no problems and runs without any graphic bugs or noticeable slowdowns even on 1920x1200.
I noticed a minor audio sync issue during the cut-scenes but except for that everything is working perfect.
I filed a report on WineHQ. Will update with link if it gets approved.