GDB looks intimidating, but once I decided to try it I'd never go back to printf debugging.

Oh yes, I've used it for many years (though many years ago). For me it depends on the size of the program and the compile time; if it's a short one and compiles quickly, I'll throw a print/puts/print/echo in there just to see what's going on.

That's what happens with "real" debuggers, in my experience! Though Codebug (for XDebug in PHP) is what did it for me, but now I'm using interactive debugging wherever I can. Beats the hell out of trying to print out variables.