Some cross-platform packages like Ruby or Qt prefer %HOMEDRIVE% as the default installation path, Google Chrome uses something in %HOMEPATH%. What's the advantage and disadvantage of each choice? What's the best choice for a simple private application (i.e. a game, where the installation should work without administrator rights)? On the other end: What would be the best choice for an industrial application (i.e. a software that controls an industrial device, running on a computer that merely exists for that purpose)?
If you want to ensure your app can be installed without Admin privs, install under %LOCALAPPDATA% - if you want to install system-wide, use %ProgramFiles%. Whatever you do, don't use %ProgramFiles(x86)%.