8800 has weak structural integrity.
If anyone has experienced problems with the 8800 with an over-responsive trackball or other strange usage problems, I believe I have found the reason. I've had to return 2 so far because of this and I still have the 3rd. After a few months of use the trackball started to activate menus on its own when I was only navigating, making it nearly impossible to use. Specifically when I navigated down my email list it would bring up the 'reply' menu, activate it, bring up a new email reply and send it all in a split second, thus sending an empty email to the original sender.
Now I admit when I go out at night I do not keep it in the belt case. I usually just slip it into my pants pocket. Anyway it seems to me the problem lies with the construction of the BB's casing. I am a product designer so I took the last one apart and its seems the structural engineering is weak on this phone and it cannot handle stress in the mid section. The anchors are not strong enough at their points to prevent bending. The PC board inside is anchored to aluminum which easily bends out of shape so once the phone bends past a certain point contact is made with the casing and the PCB thus creating a short. Even though Aluminum is not highly conductive (hence the design choice) it is enough however to wreak havoc on fine electronics. What's not clear is if the short is created with the casing that holds the PCB or the metal casing around the LCD screen. I would need BB's PCB tester to make that assumption, which, unfortunately I do not have access too. :-P
In the end I switched to the Curve and it is 1000 times better. It's lighter, stronger and compared to the 8800 I had, several more features like GPS, WiFi and a decent camera. (I had the original 8800 with none of these features.)
Anyway I hope this is helpful to anyone who either owns the 8800 or is thinking of buying one. If left in its case, most likely it will be fine but use care because as I have found in my tests it doesn't take much to bend it out of shape partially due to its slim design.
Please feel free to post any similar incidents as it would be nice to send RIM more information to help fix the issue. RIM has been kind enough to replace the phones however have not commented on my findings.