I had the issue with reboots after taking the OTA gingerbread update on my non rooted X. Came to find out it was the Advanced Task Killer (Froyo) version that was the culprit. Uninstalled it and my phone has never yet rebooted.
Greetings all. Long time lurker first time registering and posting. I absolutely love the Android OS and looking forward to learning how to root my devices, peruse the different ROMs and finding out the full potential of Android.