As the title suggests, this pack is full of shaders, Doom 3's "interaction" shaders to be exact. Basically, everything I've done so far on the lighting side of idTech4.
Inside are 14 different lighting models used, and each come in 3 different flavors (normal, parallax, and relief mapping) for a total of 42 shaders for Doom 3. The lighting models used range from the simple Phong and Blinn-Phong to the more complex and phisically accurate Cook-Torrance and Ashikhim-Shirley. Each model also includes rebb's ambient lighting (simpified) and rim lighting (although a couple don't include rim lighting as it doesn't work well with non-Lambertian diffuse... still working on it). The parallax shaders are setup to use either a height map or normal map by simply changing some comments with the height map used as default. The relief shaders require a height map and also (unfortunately) an nVidia card. I recommend downloading the original relief mapping mod to get the "normal2depth.exe".
This is an on-going work in progress as I plan to keep adding more models as I find them and any features I find globally beneficial. For instance, I had ambient aperture lighting(pulled from Humus' tech demo) in at one time but not all textures benefited from it (plus it really requires a specific aa normal map to shadow correctly) so I excluded it but the rim lighting looked good enough for everything so it's included. It really is a shame id designed D3 (as well as, Q4 and ETQW) like this, Human Head is the only studio to do shaders right.
Also included is a little test map I used while writing these. It has a player start but is more designed to be used from within the editor.
Anyways, here's the file. If anyone finds any bugs or artifacts, let me know. These shaders were tested but not extensively tested.
Update 11/10/09:
Released a pack update. Details of changes are in the readme. Also changed the name of the pack to idTech 4 Shader Pack.
Update 11/27/09:
Released an update. Again, detail are in the readme but here are some things of note. I added a self shadowing term (not to be confused with self shadowing bump mapping). I also added ATI compatible relief mapping shaders as well as fixed the problem with relief mapping where diffuse/specular maps would be scaled wrong if they use a different scale than the normal map, like if the normal map of diffuse texture A is scaled to half its size to work with diffuse texture B which is unscaled. This was because all three textures were using normal map's texcoord. With just a little extra math this was able to be fixed.
I also wanted to point out that it is becoming impossible for me to check over every shader to make sure they're clean so if anyone finds any broken shaders or bugs, please let me know.
Edit: Added some before/after screens to show what I mean by self shadowing.

Shader pack:
http://sikkpin.fileave.com/idTech4ShaderPack_v1.3.rarTest maps (D3):
http://sikkpin.fileave.com/D3_testmaps.rar