How much patience did people have back in the 90s when broadband and computers were slower? (Hell, it sometimes took 30 minutes just to dial into AOL without getting a busy signal.) Now that computers and broadband are faster, do you think people have just as much patience as before or less?

I'd imagine that, until broadband becomes truly instant, you will have a need to ensure users that the page is still loading. A user's patience will never grow. It will only shrink. The least we can do is buy ourselves precious seconds by using a progress bar. It is the difference between "Your call is important to us, please hold" and "You are now 5th in line to be answered. Please hold." The illusion of progress goes a long way in fooling the user's brain into having just a smidge more patience.