I readily admit that I, too, have PSDs floating around on my PC. They date from my earliest days with PS, when I naively used "Save As" with the default format (PSD).
Since then, as I have gained some of the Wisdom of the Sages (Tarzan, Jeff, Michael, among others), I have used only TIFFs (or JPEGs when needed for the Web). There have been a few times when I have needed some of the images that were saved as PSDs, and it turned out that those times required some sort of submission as TIFFs, so I had to go into PS and save new versions.
My personal conclusion: PSD => nuisance (eventually, if not right away), while TIFF => OK for the foreseeable future.
As for your comparison of KenR to the Onion in that other thread, I must object. You are absolutely right on about Jon Stewart and Stephen Colbert and Fox News, but I find the Onion to provide frequent chuckles in almost every paragraph, while the few times I've glommed KR's scribblings, the seriously entertaining bits and the reasonably useful bits are few and far between.
Life is too short to spend time on KR's site or on Fox News, IMNSHO.
P.S. For solid news I also rely on Paul Krugman for economic news and Gail Collins for political reality checks, both on the NY Times.