Greyowl,
The default setting is "notice", which should suit most users, but to each his own. If you change the setting to "info" for instance it will generate lots of logging entries in the info section, which is fine if you take the time to read them and can make meaningfull use of them, but then from time to time, you would also have to clean them out as well. Perhaps you should give each of the levels a trial and then decide which setting suits your application best.
I personally think the default is a good choice unless you are chasing a specific problem.