The only app I can think of that's missing in Post #1 is an Audible app.
I don't have an Audible subscription yet, but i would if there was a client for N900... ;-)

Other than that, the list is more than complete for me.

Most important for me (in more or less random order):
- good offline navigation
- good office suite
- spotify client incl. offline playlists (Meespot seems to do...)
- dictionary for several languages
- usable linux shell with functionalities like ssh server and client,... (I hope this is really part of the basic OS)
- music player which supports gapless playback
- fahrplan or similar app for public transport schedule