Thats the only thing that i miss from time to time, a proper phone, i mean it´s still most tablet with phone features, that doesn´t work that well some of the time... I can make calls and most of the time answer them (problems accur when cpu i maxed or using fm radio player or LXDE or Mypaint...)
Thought about replacing my N900 with a HTC Desire HD or Z for a short moment, but came around and reflashed with PR1.3 and it´s as new again just with alot more features and oc'ing and queen b's
I think when replacing at some point it will be with a droid phone unless Nokia comes around and gets flash 10.x with lets say N9/Meego