Compiling a list of useful utilities for modeling and skinning. If you know of one please PM me and I will take a look at it. More to come as I get around to learning some of this stuff.
Thanks goes to : Wnn,
Graphics Editing Programs
Open-Source (Free) Graphics program on par with photoshop, but harder to use.
Jasc Paint Shop Pro
Second to Photoshop, much cheaper, and easy to use.
Probably the best available, but rather spendy.
30day free trial, but some older version can be found that are free.
3ds Max studio
Best on the market. Massive ammount of support and tutorials available. Price is pretty steep
Valve endorsed modeler, is free. Integrates well with source.
Compilers And GUIs
GUI StudioMDL 2.x / Source- GUI wrapper
GUI StudioMDL 2.x provides access to all the same functions and parameters as the command line based Source StudioMDL compiler, but through a simple Windows based graphical user interface.
VTF Explorer is a tool for viewing and extracting Source Engine format texture files (.vtf's - Valve Texture Files). Program allows you to view whole folder full of VTF's either from hard disk or .gcf file as a collection of thumbnails. You can view all frames, mip levels and cubemap faces of VTF files as well as read their flags. You can also use VTF Explorer to extract files from Steam's .gcf packages.
Windows XP / 2000 VTF Shell Extensions
These are a pair of Windows XP/2000 shell extension which plugs into your OS and allows Windows to show a thumbnail of the VTF file when browsing in Thumbnail view, or info about the VTF file in columns in details view.
Source MDL Texture Info
MDL Texture Info is a quick console app that will tell you the textures used by a MDL file from a game using the Valve Source engine. It will list the textures used by their VMT file plus the folders in which it the model will look for the textures.