Universal Extractor

Universal Extractor is an application that lets you extract files from all kinds of archives and installers. You can use it to extract resources from Windows Installer files, Inno Setup and NSIS executables, InstallShield packages, MHTML files, Microsoft Compiled Help files, any archive type that can be extracted with WinRAR (rar, zip, ace, cab, 7zip, etc), CD-ROM images, Linux packages and more.

I find this useful because it provides a consistent way to see files that contain other files. You may need to extract the files from an installer to create a portable version of an application (like this portable IE7), to read the help file before installing it or to get a file. Instead of using the command-line and different small utilities, you can try Universal Extractor, an open-source Windows application.