As stated, nearly all of the command line, registry based, and related utilities only list those programs that install and place proper registry entries in the proper keys.
Just listing all of the executables on a system is not very helpful either, as you have a lot of sorting and elimination to do to make a simple list.
I have used Win Audit and it gives a fairly detailed list.
SIW is another viable option.
http://www.gtopala.com/
The real question is what do you need / want to do with this information?
If this is for a business that wants to make sure that only licensed and approved software is installed, you really need to lock down the computers and install monitoring software.
Chas