I am still using my n900. Love the open phone and hate that I am missing the most basic of apps:

1) PIM - sport for Task Descriptions. (that can sync with outlook)
2)Search the ability to Search PIM info. (IE: notes, Tasks and other calendar and contact info, and SMS and IM data.)
3) a simple app that lets me choose the dealt programs.
4) an app to allow for a qwerky portrait keyboard.
5) Augmented reality translation with dictionary for many languages. (like the Iphone app.)
6) a note taking app that recorder audio and allows you to navigate the audio by the note taken. (something that would work similar to Livescribe Pulse Digital Smartpen but on my phone.)