I have to have one for my film as well as my dissertation, preferably the same for both. But, what is a 'voice', leave alone 'my voice'? Also, why is it important?
Maybe it is something akin to a personal style (both aesthetic and political). Perhaps, instead of thinking about all my influences separately, what I need is to think of them holistically. It is how I combine these threads and produce a pattern that transcends the individual colours and textures that will determine the nature of my voice.
Theoretically speaking, I need to stop swimming in the theory. Do I know enough to last once I'm out of the water? Probably, but the water is not going to disappear. It is always there to be used as an aid.
As to the importance of the voice, I know intuitively that it can make or break a movie or a book. This is not to say that texts should be read as per the intentions of the auteur, but more so that the voice will come through more strongly if it is a subtle yet all-encompassing presence.