Problem coming out of Roaming mode?
 

This MAY have been my problem (see Fun while it Lasted thread). I noticed the triangle icon. Have no idea why since the signal where the phone was should have been sufficient. Is it possible it's having a hard time getting off the roaming SID and back on to Sprint's???? I'd be very interested in hearing from others.

It's funny you mention this because I just dealt with the same exact problem while traveling to New Orleans. I had a great EVDO signal when I first got there but had to soft reset my phone because Outlook was acting up. When the phone rebooted, the triangle popped up and I couldn't get it to lock onto an EVDO signal. The only thing that fixed it was changing the roaming settings over to Sprint only. After I did that, I toggled flight mode on and off and even though it took a few minutes, it did lock back onto an EVDO signal. Once it did, I switched back to Automatic mode and it worked fine after that. I was able to repeat this scenario later in my trip so there's definitely something wrong with the phone coming out of Roaming mode and locking onto EVDO.

VERY interesting!