Turjake: It seems that the GOG version has been improved. It already has support for different resolutions without any need for mods and file editing. However, the mods can be used to improve other aspects of the game.
dukenuke88: so it can do pretty much any resolution without any consequences?
As the others said, up to around 1920x1080/1920x1200, then yes.
BTW you should check the mods threads and get kentie's loader(called deus exe) and put it in your game install where told to via the read me. It allows for setting custom resolutions before jumping into the game and also custom fields of view for the different aspect ratios(16:9, 16:10, 4:3, etc.), along with integrating a GUI mod you can turn on/off to shrink or enlarge the GUI in-game......it also allows you to order your mods and pick which to enable and disable at any given time.
Kentie also makes a great DX10 render for the game which also makes the game look a bit crisper.