I have had this issue 3 or 4 times since the 2.0.1 update.
I'll be in the messaging app and for some reason unknown to me I will get a force close error. I force close then EVERY text message has been deleted. I have no idea why. The first time this happened it was a little different. I couldn't get text entry to work on the SMS (i could type...but no text displayed...however auto correct still thought it was...weird) so I powered off and did a battery pull and then they were all gone.
Happening to anyone else? Soultions?