Yep, I've played Thief 1 and 2. Both amazing, awesome games. I'm ashamed to say, though, that I didn't get around to playing them until earlier this year. I knew everyone praised the Thief series as being fantastic, but it was the medieval setting that kept me from playing them until now. I'm not really into medieval, fantasy games.
Thief 3, I'm maybe 1/3 of the way through it. I started playing it immediately after I finished 1, 2, and the T2X fan expansion. But it's just not the same, and I've played it sparingly since. Doesn't hold a candle to the first two. It looks and plays like an Xbox game . . . it suffered from being a bad port. I actually like it even less than Deus Ex: Invisible War (aka Deus Ex 2), and I didn't think that was possible. Thief 3 makes DX2 look good by comparison.
There are a bunch of patches and mods for the Thief games, to make them run well on XP and Vista and the newer graphics cards.
Thief 1
Thief 1 Patch - Only meant for the original release of Thief 1, if you have Thief Gold then don't use it
DDFix - Makes the game run better on newer graphics cards and dual or quad core processors
Widescreen PatchThief 1 AI Mesh and Skin patch - Upgrades the character models to have better quality
Thief Enhancement Pack - Updates some of the models and textures
Thief 1 Sound Enhancement Pack
Thief 2
Thief 2 PatchMission 2 Fix - Fixes a problem with the second mission in the game
Mission 11 Fix - Fixes a problem with the eleventh mission in the game
DDFix - Makes the game run better on newer graphics cards and dual or quad core processors
Widescreen PatchThief Enhancement Pack - Updates some of the models and textures
NTEX - Big upgrade to the quality of the textures in the game
Thief 2 Sound Enhancement PackT2X - Fantastic, high quality single player expansion for Thief 2
Thief 3
Thief 3 PatchDEF - Fixes Thief 3 to work on dual or quad core processors
JohnP Texture Pack - Upgrades the textures in the game to higher quality
Minimalist Project - Changes the gaudy Xbox-style user interface to be more like the original Thief games
Widescreen Patch
For the patches/mods for each game, I listed them in the order you should install them. Installing them in the wrong order can cause problems. You'll notice that some of the patches work on both Thief 1 and 2, so no need to download those twice.
For Thief 1 and 2, you might need to add the line safe_texture_manager to the end of the user.cfg file. And you need to run them in Administrator mode, or else they'll crash. You might need to install the
Indeo codec as well, for the cutscene videos.
For Thief 1 and 2, you might also need to use the Compatibility Mode feature Tim.H talked about. I had to set Thief 1 to Windows 2000 mode to get it to work 100% properly.
For Thief 3, you may need to turn off DEP on XP if you have it turned on. On Vista, DEP is always on by default so it has to be turned off in order to get Thief 3 to work. If you don't know what DEP is,
visit this page to find out what I mean.