I think the worst was Windows movie maker, which used to seem to just randomly choose a time it might take and do a bad job of self correcting on the way. Oh, and of course there's a relevant xkcd, http://xkcd.com/612/
I think this is something slightly different in that it's non-blocking.
The progress bar provides users with feedback as to the current status of the page they have requested to load, but it doesn't get in users' way and the page loads and renders as assets become available (unlike in SWF where all interaction is halted until the entire site has been downloaded up front).
Is HTML5 audio available on all browsers yet? I remember for Cut the Rope that they claimed that HTML5 audio for games only worked in IE, and that for whatever reason Firefox/Chrome/Safari didn't work quite right and needed a Flash stub.
I think the problem was that SWFs so frequently needed load indicators. Sure, progress bars make the time seem to go by quicker, but what's better is actually being quicker. Progress bars were a crutch, but the pages were still dramatically slower, that's why we all hated Flash sites so much.