I just never get tired of watching SPJ talk. He has an amazing ability to explain complex ideas in a meaningful way, not to mention his obvious natural enthusiasm for the subject.
It's also great to attend any talk where he's in the audience, because he always finds a way to ask questions which intentionally create opportunities for the speaker to look better by diving off into some interesting subtopic or area of technical detail that they've overlooked. A real talent.
SPJ also writes amazing papers. He always has a novel, practical idea, and he explains it clearly. For example, here's a paper he co-authored on Software Transactional Memory in Haskell:
Notice the care taken to explain why STM is important, and its advantages over traditional locking (ease of use and composability). There's also two great new theoretical tidbits in this paper, the 'retry' and 'orElse' operators, which significantly expand the power of STM.
SPJ's good example has filtered throughout most of the Haskell community by now. I love programming in Haskell because it gives me an excuse to read these really cool papers (and it stretches my brain until I understand them).
It's also great to attend any talk where he's in the audience, because he always finds a way to ask questions which intentionally create opportunities for the speaker to look better by diving off into some interesting subtopic or area of technical detail that they've overlooked. A real talent.