Maybe this is just my lack of experience speaking, but I find debuggers incredibly difficult to use when dealing with interactive software (which is most software I work on). Hitting a breakpoint freezes my interaction unless I configure it to print something, and configuring it to break conditionally requires knowing some obscure incantations that I can never remember off the top of my head (and that in turn require their own debugging). So it boils down to: should I spend 5 minutes figuring out how to set this conditional, print-only breakpoint? Or should I just put in a printf? The solution, at least to me, is obvious.

(With that said, when I have a nasty bug that requires squishing around in the guts of my program, breakpoints are invaluable. But it's a pretty huge hammer that only comes out on occasion.)

EDIT: I wonder how useful an editor that allows inline debugging code would be? Instead of setting breakpoints in your IDE and then configuring them in an individual window, you'd enter a "debugging editor" mode that would allow you to add debugger-only code for things like conditional breakpoints and printf statements right alongside your normal code. The original source files would not be edited, but while in this mode, it would appear as if they were. (Maybe the debugging code would show up in red.) That way, you could easily access all your local state and implement complicated queries without ever leaving the context of your code. In other words, it would be just like printf debugging, but once you no longer need to debug you'd just collapse those statements out by leaving the debugging editor mode and your original code would be unchanged. Perhaps this debugging code would not compile along with the rest of the code but would instead use the debugging hooks that normal breakpoints use, unless the conditions are particularly complex or something. Just a thought.