In a small project I tried to reduce the application's EXE size. It seemed that I needed to include unit Forms because I needed the application's startup directory.
I then remembered that ParamStr(0) contains the same information as Application.ExeName and my EXE file shrank from 290kB to 43kB.
After using UPX it now has a size of only 22kB!
// this version needs unit Forms
uses
Forms;
begin
sPath := ExtractFilePath(Application.ExeName);
end;
// this version does not!
begin
sPath := ExtractFilePath(ParamStr(0));
end;