As part of Apple's iPhone 4 press conference today, CEO Steve Jobs took the opportunity to bring out a BlackBerry Bold 9700, HTC Droid Eric, and Samsung Omnia 2 and highlight each of those devices dropping from 4 to 1 or 0 bars as well.
Jobs also pointed out that the formulae used to calculate and display bars isn't standardized and everyone works out for themselves how they're going to do it. (As of iOS 4.0.1 Apple is now using AT&T's recommended formulae).
Lastly, he pointed out that Apple's highly visible black bar at the bottom left of the antenna array made the problem spot easier to find on iPhone 4.
[Slashgear, Android Central's response]