Email - Modest crashes my desktop at least every couple of days. Claws isn't very user friendly, I can get it via a web/mobile web interface, but that can be slow/minimal interface.

Ebooks - As long as they don't have DRM, so you have to work harder to find non-DRM books, or go through some gyrations to get other solutions set up, not point & click easy.

Music - Again DRM is a hang up. Download non-DRM, or rip my own, transfer via usb, card reader, etc.

Video - currently most need resized/re-encoded, we do have youtube and flash though.

Directions - need a gps, N810 GPS not very good, buy expensive not updated program, no offline routing, other issues.

I think most average/normal users are looking for easy point-and-click solutions. None of the above really fall into that category. Other options offer simpler solutions that require less work / fiddling. Until Maemo can offer the same, most users will shy away from it. The N900 may alleviate some but not all of these issues