I know you are passionate for Linux but man, listing those free apps as advantadges of Linux is silly considering openoffice, thunderbird, the gimp and inkscape are also available for windows (and mac osx, shall I add).
You could save the money from Office, Photoshop, Outlook and Illustrator without switching to Linux since all those applications run on Windows too. Nevermind the fact that functionality might not necessarily be the same (do the Gimp and Inkscape provide the same tools that Photoshop and Illustrator do?).