[gumby]

non-bracket is useful and informative in some cases when used properly (your local style guide takes precedence of course). I would never write

   if (condition)
      Foo(x)

for the reasons you said. But it can be very useful for a block of "single liners":

  /* clean up input before passing it to flaky_external_module() */

  for(; !isspace(*p); ++p); 
  if (!isdigit(*p)) return INPUT_ERR;
  for (char *i = p; *i; i++) *i = toupper(*i);
  ...

  flaky_external_module(p);

Basically a small block (that pretty much fits in your fovea) that does a bunch of minor tasks. Spacing them out would actually confuse the code.

[tmuir]

I contend that the brackets always make the code more readable, without exception. It's the normal case. All other variations make you think "something special is happening here, I'm going to have to parse this carefully". The for with a semicolon at the end is easy to overlook. The return in the middle of a function in the middle of a line is easy to overlook.

Spacing code out makes it more readable and maintainable, not less. It brings consistency, and it is more prepared for the inevitable change. I think maintenance is the driver of all code style. When you make tight one liners or forgo braces, or use the ? And : operators instead of if and else, you're not really saving time, you are deferring work, in a lot of cases to another programmer.

[gumby]

Well, as I said, these determinations are up to the house style.

I prefer that blocks of code hold together -- think of them as paragraphs. Spacing each sentence of a paragraph out is similarly confusing. But as you say, YMMV.

I find return is_valid(result) ? result : ERR_CODE; common and clear, but perhaps you don't.

I do think that any style guide should forbid while and do..while simply because for has become by far the looping construct of choice in C.

In all cases the point should be correctness and clarity, not showing off that you use unusual language features.