I recently packaged up a piece of software for distribution, and I would never have a ZIP file to unpack. It HAS to be a standalone setup.exe which installs to Program Files/program so nobody has to make a decision. Access is with an icon in the system menu. And there's an uninstall. It's made with NIS Edit, which is a great program.
I sell a downloadable program over the Internet, and so am fairly familiar with the notion of writing installers. (Note that this is a B2C program for highly non-technical users.)
Here's life:
a) Users will click past any screen you put in an installer, even if it comes with pre-checked options for reformatting their C:\ drive and shooting their dog.
b) Every additional screen in the installer costs successful installs, and hence conversions (if you're using free trials).
Accordingly, I don't ask users where to install to. I ask the system where program files is and it goes in the default directory there. Period. I don't ask them what to name the shortcuts in the start menu -- its named after the product. Period. I don't ask whether to drop an icon on the desktop, I do it. If they want to delete it they can hit a delete key as easily as unchecking a box, but it saves 100% of users another screen to process. etc, etc
