While it is common to see Simpsons' Chess Sets, featuring Homer as the King, and Franklin Mint Civil War chess sets, where historical figures are personified in the pieces, alternate influences on traditional chess pieces have been less common.
A few times I have run into more detailed, handcrafted sets featuring Alice in Wonderland characters, or Chinese Emperors (with Confucius as the King).
However, on a more creative note, a plethora of ideas of this nature can be found at www.edgewatergifts.com, where the chessmen are designed in themes such as freshwater vs. saltwater fish, High Noon cowboys, and outer space, just to name a few.
One of my favorites is, the hockey theme, as pictured here, where the characters are as follows:
Pawns - Pucks
Rooks - Hockey Nets
Knights - Referees
Bishops - Players
Queens - Hockey Moms
Kings - Goalies
Personally, I think the Knights and Bishop characters should be reversed, but that's another issue.