Going from a human state, to that of a rock, has a deeply depressing feel to it.
Not being able to walk any more, communicate, express love etc etc.
It reminds me of a song by Metallica where a soldier is involved in an explosion and he can no longer communicate, yet he is fully conscious. (Metallica - One)
Edit* I found out the video clips in Metallica - One, are from a movie called Johnny got his gun.http://www.youtube.com/watch?v=K7AFmXc0wK0
If I started out as a rock, I think the opposite would be true.
Instead of being depressed about my state, I may be enlightened by the living.
A little jealous I guess, but the thought of going from non-living to living, would make for an inspiring dream.
Similar to the way we humans may dream of having Godly powers, we can not achieve it, but the thought of being a God is enlightening, where we go from our regular mortal state, to immortal and powerful.
As an immortal rock that witnesses the living come and go, I may smile (consciously) at the thought of becoming a living being.
Perhaps I would dream of giving up my immortality for the idea of love and life.
So then, I would think of those who posses concious life, as being lucky, even though the duration of life for each individual is brief.
But overall I would be happy, just chilling :)
During my eternal existence, I would have watched a few cool movie's about dinosaurs, evolution, the development of a planet, the coming and going of entire civilizations and perhaps the dying of a planet.