I guess that languages such as Smalltalk, Common Lisp and Python are all OO-functional rather than pure-OO or pure-functional. It works quite well in practice - whenever you have some simply-structured mutable state that's being worked on a lot (and where the intermediary states are not really interesting), then OO is going to float your boat. If you have complex-structured data that undergoes transformations into many different shapes (summing, projecting, mapping, extracting), then you want to use functional idioms.
(I say "functional idioms" because, e.g., list comprehensions are a functional idiom but not conceptually tied to functional languages if you really think about it).
