How to uninstall final cut pro HD, illustrator

Location File/Folder to Delete
/Applications - Final Cut Pro
~/Library/Preferences - Final Cut Pro User Data
/Library/Application Support - Final Cut Pro System Support

Illustrator - drag the app to the trash.
Open user>library>application support<Adobe - in anything for Illustrator is in there, trash it

~/Library/Preferences - look for it's preference
However, I guess Illustrator uses far less space than FCP in the Application Support folder, so you might want to trash FCP and see how much you're gaining.