b1k3rdude: Sorry to multi post, it just erks me that all gog have done is punt a game out and exspected the players to fix it. You lot paid your money and the way its been shuffled out the door is just not good enough.
I think the problem is that they're not allowed to fix it. Square Enix is letting them sell the game in its original form; any modifications must be made on the user end. GOG was able to do a few things, like set the processor affinity to one core only, but they can't do much more than that. If any entity is to blame for not providing the fixes, it is Squre-Enix, not GOG.
What GOG
could have done was link or otherwise direct users towards the fan-made fixes available at the Through the Looking Glass forums. Fortunately, GOG forum users have already posted about those here, and it sounds like it's not too much trouble to apply them.
Speaking for myself, personally, I am happy to have an opportunity to buy Thief Gold (I had only ever played vanilla Thief) with no DRM in a convenient downloadable format, and I don't mind having to fiddle with a few things to get it to run. I much prefer this situation to one in which GOG was unable to sell it because they couldn't apply the fixes.
From what I hear, the retail "Thief Collection" also requires the player to apply these fixes themselves, is that correct?
EDIT: Official response from GOG:
http://www.gog.com/en/forum/thief/could_gog_have_done_more_with_this_release/post30