I have noticed three changes to my Droid X since the Gingerbread update that have caused some issues.
1. The backlight on the keys do not work consistently. If they are pressed, the light does not come on. I have found that if I rotate the phone, they seem to come on. According to some searching, this was a Froyo problem as well but I had never experienced it before Gingerbread.
2. I have several personalized notification sounds. About 4 of the sounds were in WAV format. Once Gingerbread was loaded, they would no longer work properly. I had to convert each one of them to MP3
3. If you go to Contacts...Press Menu key...Press More...Press Settings...Press Contact storage, the default account to store new contacts is "Backup Assistant". I use my Google account, so this change would have caused me significant issues.
If I have duplicated another post I am sorry. I looked around but did not see these issues.