I think Kay is one of the most interesting speakers in CS; he's a learned man. But I didn't find the content that great. If you want some thoughts on software architecture, programming languages, with a lot of great cultural references outside the field, I much prefer the thoughts of Richard Gabriel:
http://www.dreamsongs.com/Essays.html
If you search for his work on "ultra large scale systems", it is a lot more thought provoking than what Kay offers, and it is a lot more specific at the same time.
When watching the Kay talk, I was struck that he seems to be lumping every "good" in software engineering under the term "object oriented". Virtual machines are objects. Servers are objects. Numbers should be objects. All abstraction is objects. It was not really a useful or enlightening way of thinking about the world.
I know OOP has a different definition than what he intended with SmallTalk, but he didn't invent modularity. For example, Unix is highly modular but not object-oriented, and it predates his ideas.