I increasingly feel that there should be two separate logs, one for the user with the Error/Warning/Info information (what the user wanted to be done and how well it went) and the other for the developer with the Debug/Trace information (capture key information about what the program was doing, especially on the interface - what files it was looking for, what database calls it did etc.).

I always get complaints from users that there is too much useless stuff in the logs through which they need to go. I also think that the developer log should be structured differently, possibly to be easily read by some automation.