I just upgraded to Ubuntu 10.04 which comes with Firefox 3.6.3.
Now Google reader some keyboard shortcuts stopped working, The j/k keys are ok, but 'v', 'Shift+x' and others don't work and start the Search As You type functionality I've always used.
Warning: The 'charCode' property of a keyup event should not be used. The value is meaningless. Source File: http://www.google.com/reader/view/?tab=my#overview-page Line: 0
This did not happen with Firefox 3.5.x even though I've always had the Search as you type option enabled.