I have never attended any OOPSLA conference. But I just returned from giving an invited talk at ECOOP 2004. In preparation for this talk -- Martin Odersky had requested a provocation -- I read up on the history of OOP and I also went thru a large portion of OOPSLA and ECOOP abstracts. As I did so, I realized how much the modern OOP community has forgotten about its roots.
For other stuff, see http:/www.ccs.neu.eduhomematthias.