At my company we create Windows based desktop applications. In the past, we have created .chm files for our help documentation and have been happy with it. We have now been faced with some issues regarding the software we use to create the .chm and would essentially have to invest a lot of money to continue using this .chm creation software, which leads me to this question: Are .chm files the really the best avenue for providing help documentation?

I have done some research on creating PDFs with all of the elements that are in the .chm files such as a table of contents and links that jump to other sections in the document. Online help is not an option. Whatever solution we pick has to work without an internet connection.

So again, which type of help system is best? Are PDFs acceptable instead of .chm files? Is there another better alternative?

Update: It looks like we have to use .chm for a few reasons, mainly because of its ease of updating and distributing (only 1 file). My runner up to this would have been html help, which is essentially what a .chm is anyway.