Email client: Thunderbird
Terminal: Gnome Terminal
File Manager: Nautilus
Basic Text Editor: Gedit (But can you patch the ridiculous "find next" shortcut key to ctrl + f/enter from ctrl + f/ctrl + g?)
PDF Reader: Gnome default
Office Suite: LibreOffice
Music Player: I always felt like Banshee was the superior Gnomish music player but it seems to unmaintained unfortunately. Rhythmbox is the next best basic one IMHO.
Photo viewer: Gnome default
Yes this is one of the things that I am really annoyed with gedit. All searches (to my knowledge) in browsers and IDE's work by pressing enter to get to the new search entry.
The only exception which comes to my mind is vim which has 'n' to go to the next search entry(also completely different to gedit). But in comparison vim, excepts the user to learn a lot of new commands, gedit on the other hand should imo follow the simplicity of other GNOME apps.
To search a keyboard shortcut in the manual and then memorize it for such a simple editor is just tedious and irritating.