One thing I love about Windows Installer is that you can mark files as 'vital' for example the exe or dll. When a user removes or alters such a file and wants to start the application by clicking on the shortcut in the start menu, the Installer jumps in, asks for the media of that application so it can re├»nstall the missing vital files.
Of course Installshield wants to rape this nice technology by mixing it with theirs. It's a shame that other product teams from Microsoft (like Virtual PC 2004) are using that mixed installprogram.
On the other hand, Microsoft did made a good install technology but they didn't made a program to create installers that use the tech to it's fullest.

On the api-side, is there a site from ms where you can see a list of all api's, with an explenation of what you can do with them?