A more extreme form of whitespace sensitivity in C are the two following statements, which are identical and differ only in their whitespace.
x = y++ + z; x = y + ++z;
That's a pedantic argument. What "whitespace sensitivity" means when talking about Python/Haskell vs other languages is fairly well-understood (use indentation to delimit blocks).
For my money, I'll take Python's consistent use of ":" to start a block, though.
For instance, in C the following lines have different semantics: