Update: As a number of readers have pointed out, there seems to be an issue with how many bars are displayed on screen -- perhaps even a correlation to how it's being held in the hand. According to Walt Mossberg's review, Apple has acknowledged the issue as something that has to do with "the way the bars are presented, not the actual ability to make a call," and that a fix is forthcoming. Indeed, as noted in our review, we've had "far, far fewer dropped calls than we experienced on our 3GS." We're not seeing very many videos showing more dropped call, but the bar change is interesting. Still, to be sure, we're adding another poll.
Update 2: Our iPhone 4 purchased in Japan has a pale yellow bar along then entire bottom edge. Picture after the break.%Poll-48460% %Poll-48475%
[Thanks to everyone who sent this in]