Final answer:
The theme of the story 'The Sitar Blues' is that familiar skills can be used in unexpected ways.
Step-by-step explanation:
The best theme for the story 'The Sitar Blues' is Familiar skills can be used in unexpected ways. This theme is evident in the protagonist Nihil's longing to play the guitar instead of the sitar. Despite his initial disappointment, Nihil discovers that he can use his familiar skills on the sitar to create unique and unexpected music.