For those of you using Vista (or XP, I suppose), you might be taking advantage of GOG.com's nice 256x256 icons included with each game. I have been, and I've been wanting to make my other games match that appearance. I've done a few here. You'll have to convert them to ICO yourself since I can only attach images, but a simple website (Google one) should do the trick.
Let me know how ya like em, or if there's others wanted. Hope this post is by the forum rules and all, and that GOG doesn't mind!