looks like the majority of those complaining are female. Wonder if long hair could be interfering with the sensor and causing problems since the update seems to have changed things.
Just as a data point - I have not had any of these problems with my Droid. It is one of the "first" in that I got it back in Nov. 2009 the day they came out (well, not quite true - THAT one randomly rebooted even while sitting on a desk and I had to have it replaced 2 days later, but still I got my current one within the first week of availability). As far as I can tell the proximity sensor is acting like it is supposed to. Screen blanks on a call when the phone is up to my ear, and turns back on when I take the phone back away.
I am also having issues with my original Droid since the 2.2 update. I bought mine within a week of the original release (Nov-09) and had issues with the proximity sensor until the first update. Everything has worked fine until the 2.2 update.
I typically have issues when I use my shoulder to hold the phone to my ear. The screen turns on, and something happens... sometimes it hangs up, other times it switches to other screens (usually the home screen).
The times it actually does not hang up on the call, it is *extremely* frustrating because it becomes impossible to return to the call-in-progress screen. It returns to the home screen, the display is still ON, but as soon as I pull it away from my ear, the display turns OFF within 1-2 seconds. I hit the power button, slide to unlock, and the home screen displays briefly (1 sec) before the display powers down again. Hit power again, sometimes it displays the home screen briefly (1 sec), other times the slider; either way, the display always turns off before I can pull down the notifications bar and return to the call in progress. I am basically stuck until either the other caller ends the call, or I power down the phone and turn it back off.
I've read in other forums that it may be related to holding the phone at a certain angle while talking, but have not seen any resolutions for the problem.
I hate to be the bad guy here. Well, not really. lol ..... I got my droid when they first came out. Since then I have updated 3 times with OTA's. I have rooted and gone back to stock, I have even had it on AT&T and T-Mobile networks. But no matter what i do with this phone, I can't seem to be unhappy with it. I love my Droid, and anyone who has one when they quit selling them for good, will have something worth money to the people that know what they are doing with them. Perhaps you people are just hard on your phones. I know my sons are. Just take a bit of advice, be nice to your equipment, and it will do the same in return.