I have been programming professionally since 1986 and still nothing beats logging or having chunks of specialized code to do dumps of some data to files so you can analyze them with tools better suited for the purpose. Ideally though you don't want to have to modify the code to diagnose the problem especially if it's a crash caught in the wild and you have a chance to live debug it. I would love more useful visualization tools in the debuggers (mostly VS for me) that would be very helpful in all situations like debugging crash dumps.
Most of the data I work with can't be visualized by printing. (I mostly work on 3D and video.) But I have found it invaluable to log data, then read it into another program. Sometimes I can just bing it into a spreadsheet and plot it, other times I need to write something to display it or analyze it. It's definitely an under-utilized technique!
