I think stereoscopic 3-D for animation is a neat concept but for live action films i could care less. Except the fine line between what is live action and what is cgi animation is very thin these days. 90% of New hollywood blockbusters these days could be considered animation with all their cgi fackery and nothing real.
As for the Avatar film itself i think it could have a nice element of romance as well as be an action epic, the terminator meets titanic. Can Cameron pull it off, i would be willing to give him more of a shot than lucas or spielberg who have proven time and time again in recent years that they lost the touch for making good films.
Not that Cameron is perfect either. Season 2 of dark angel was pure shit, and his script for spider man was almost as awful as jj's was for superman.