PascalCase or camelCase (note the capitalization of the first letter, that's the difference between the two) basically always.

I really like kebab-case, because I’m a lisp aficionado

Once I was checking somebody's code against a coding style and asked him why he capitalised a certain identifier that wasn't a type. His reply was along these lines: This word is a German noun. In the German language all nouns are capitalised. It is better to have the identifier look like the real word, because it uses less cognitive resources. Your IDE can tell you about the nature of the identifier. Your name should only reflect how it is used.

I kinda liked the idea (and maybe forced him to conform to the rule, I don't remember). In the end I've come to appreciate, when you can use identifiers that really look like normal text.

eat_French_cheese(new Le_Curé_Nantais()); {Not a memory leak - the cheese is properly consumed/destroyed by fnc}

And I hate if the compiler allows to have different identifiers that only differ in case. E.g. "RailsExpr" and "railSexPR" shouldn't be allowed coexist in the same code. (Neither should indentation with tabs and indentation with space coexist in the same file).

snake_case for variable names because they seem to be holding something in their underscores. camelCase for functions because verbNoun looks good. PascalCase for classes because it looks like it's a level above that needs to be instantiated before getting used.