The Oscar for Best Sound Editing is particularly difficult to predict because of the one hand we have The Dark Knight that seems to be razed in all technical nominations as a kind of compensation for not being nominated for an Oscar for Best Film and it is the most favorite to win the Oscar for Best Sound Mixing, which are categories that often couples.
On the other hand we have Wall-E that has not been nominated for Best Film, and many people had hoped that. In the first half hour initial Wall-E there is no dialogue as the robot protagonist is alone on Earth, so what you see and what you hear is of particular importance. For this half-hour talks with Wall-E I think will win the Oscar for Best Sound Mixing The Dark Knight having a great competitor.
The Wrestler Attention is also nominated for Best Sound Mixing and could be a surprise, although I do not think that happens.