Amanda, the ex-junkie bitch that Dr Gordon told Adam that the detectives took him to see.
The "think of it as a reverse bear trap" girl, the survivor.
I have wondered if the third is going to be any good, apparently, the producer/director of the first two died before filming on the third even started...
There is also a VERY well done comic out there called
"saw: rebirth" by IDW comics...fans of the film will enjoy this one a lot.
***SAW 2 SPOILER BELOW***
I think that the "surprise" in the third one, will be that the original jigsaw will be assumed dead throughout the film, and will make an appearance at the end, having gone into some kind of remission. I say Amanda will probably get killed by one of her would be victims, who will then go to escape only to "surprise" run into jigsaw.