Mine would be a parang or kukri style knife.
Yes it's large, but different parts of the blade are designed for different jobs, and if I was in a survival situation I may be moving a lot and need to build shelters and get wood quickly.
The finer part of the blade can do more delicate jobs. It may not do some jobs like fine carving, but in a true survival situation, who has time to sit and twiddle when there is a lot to do, especially if you are on the move and setting up a new camp everyday.
However, if I was thrown into a survival situation right now, I would have my swiss army knife and my original leatherman which is about 25 years old and never let me down. Both live on my belt so they would be with me.
Phill