Hi!
im starting this thread to help all pc fallout 3 owners to help solve all these errors and bugs. Since the patch is prety useless. If you have experienced any bugs or errors throughout the game and know how to fix them, please submit there here.
thanks,

The most common one I've encountered is that it randomly crashes to the desktop. The fix that worked for me was to edit the settings in ffdshow so it was not used while running the game.

If you have the K-Lite Mega Codec Pack installed in Vista, follow these instructions:

• Go to Start->Programs->K-Lite Mega Codec Pack->Configuration->ffdshow video decoder
  
• In the window that appears, select the "DirectShow control" option in the left pane, and add Fallout3.exe in the box next to the checkbox that says "Don't use ffdshow in:".
  
• Repeat this for the ffdshow audio decoder as well.

That fixed it for me.

Is this a Vista issue only or does this problem occur in XP machines as well?

No idea. I suppose it's worth a try if it's happening to you though.

This issue does occur in XP SP2. I tried out the ffdshow setting and seems to have fixed it..at least playing for 1 hour without any crashes.