This is one of these easy hypothetical conundrums to postulate, but before I make a firm decision, I would need a bit more information. For example, what are my available personal resources? Do I have the interior resources of my TARDIS, even if perhaps the ability to dematerialize has been taken away? I assume that this 'Desert Island' is surrounded by an ocean -- does it therefore have eatable fish in it, or nothing but poisonous, radioactive eels? Alternatively, do I get to choose the friends I can bring, and do they bring their own resources with them? There's so many things to consider here.
Oh, you mean I have to make a choice now, and forget all my practical wittering? Very well, I choose friends. No, not because I intend to resort to cannibalism, but in a crisis, the more creative minds you have going, the more likely one of them will come up with some kind of workable solution to our problem.