I\'ve been reading about Singleton pattern for last few days. The general perception is that the scenarios where it is required are quite few (if not rare) probably because
If you haven't seen the article Singletons are Pathological Liars, you should read that too. It discusses how the interconnections between singletons are hidden from the interface, so the way you need to construct software is also hidden from the interface.
There are links to a couple of other articles on singletons by the same author.