Another syntax that tries to make S-expressions friendlier is “sweet-expressions”: http://readable.sourceforge.net/. Its main change is using Python-like indentation to allow you to remove a lot of parentheses. It is backwards compatible with S-expressions.
I find that much less readable than S-expressions. Well-formatted S-expressions actually make it pretty fast for me to find what I'm looking for in code, probably faster than in C-like languages - and I mostly use languages which are more-or-less C-like.
