Just because I have to ask, what exactly is a "desert island" considered?
Is it an island that is a complete desert wasteland? Or do you mean a "desert
ed island" which has the potential for some plantlife to forage off of.
If it's the former, then I would think a $#!tload of sunscreeen and water in addition to some survival expert would be prudent. If the latter, then I would go with a good quality machete, toothbrush, toothpaste, and my favorite actress for "entertainment" purposes