kepo-ing Zz85

for some common, necessary, commercial applications.

Office Productivity
Microsoft Office -> Open Office

Photo / Imaging Editing
Adobe Photoshop -> GNU Gimp

Web Browser
Microsoft Internet Explorer -> Mozilla Firefox

Email / Calendar Organiser
Microsoft Outlook -> Mozilla Thunderbird / Sunbird

Vector Graphics
Adobe Illustrator -> Inkscape

Desktop Publishing
Adobe Indesign-> GPL Scribus

3D Modeling
Autodesk 3ds Max -> Blender3D

Music Typesetting
Finale -> GNU Lilypond

Vector Animation
Macromedia Flash -> Synfig

Just a small list that come to my mind. Feel free to add more.