If you're examining floor textures in Thief: The Dark Project, you're not paying enough attention. Stop staring at that cobble and watch for the guards strolling across it, taffer. Still, given that the game is old enough for a metal dealer's license, I can see why you might want to freshen it up - teenagers can be an awful lot.
Many moons ago we peeked at the first release of the Thief Gold HD Texture Mod, a fan project giving the game a shower, a haircut, and £50 in H&M vouchers. The mod has now reached version 1.0, making more prettier than ever.
You can find the changelog for the latest version over here. What'll we find in there? More new textures, of course, lightmapped water and lava, some new higher-poly 3D objects, a new settings tool, and so on. Looking at comparison screenshots, yep, those are some nice changes.
Project lead Bentraxx is also behind a texture mod for Thief II: The Metal Age.
Here's a recent-ish video looking at v1.0: