I like schemes that have an explicit input of n random bits (or where you can at least have a good estimate on the entropy.) With the Schneier Scheme I can not be sure of the actual entropy of my password. Maybe my brain only generates a relatively small set of sentences which can be reverse-engineered from my comments on HN? :-)

A good algorithm would take n bits and map them uniquely to a set of strings that are easy to remember for a human. The apg utility does something like that.