Web Browser: Firefox unmodified (e.g. no Ubuntu start page)

Email Client: None, users still using desktop clients know what they want and how to get it.

Terminal: No preference

IDE: None, this should be chosen by the user if they want one.

File manager: No preference

Basic Text Editor: No preference

IRC/Messaging Client: None, same situation as email

PDF Reader: No preference

Office Suite: LibreOffice

Calendar: Like the calendar the clock opens (no preference) or a calendar you can add events to (does a modern desktop calendar for Linux even exist)?

Video Player: VLC

Music Player: Whatever is least bloated

Photo Viewer: Whatever is least bloated

Screen recording: None, most people don't need or want this.