What are you commenting and why? There isn't, IMO, any hard and fast rule.

My opinion is that most of the time, most code does not need commenting upon. But your public interfaces should always be commented. In my code what I intend to be public is generally fairly obvious - it is what you see comments next to. :-)

I explained my views in more detail in the thread starting at Re (tilly) 1: What you want and perl advocacy gone way wrong. (In that thread look for the post by IO, really.) I would also recommend The Pragmatic Programmer and Code Complete for two other books that offer good advice about the issues that commenting raises.