Thanks Sean, I've actually already read Smalltalk Best Practice
Patterns, the advice and info in there is also highly relevant and
approachable to Rubyists (any good OOP language, really). I'll check out
the other two along with Pharo Smalltalk it looks like.
I've also played a little bit with Fancy, a Smalltalk-like with some
inspirations from Ruby and Erlang for the Rubinius VM.