MakeMsi Dennis Bareis
Free powerful but easy to use multiplatform html preprocessor. Includes external files. Imports SQL (and delimited text files). Useful for automated web site development and ensuring a common look and feel. Supports macros and conditionals.
MSIDIFF is freeware to compare or disassemble Windows Installer databases (a "MSI to TEXT" utility). While it is a command line based tool, the installer creates shell extensions so that it can be invoked by right clicking on a file in Explorer.