Since I left ie behind firefox has been good to me.
With the growing library of extensions and plugins I couldnt make the move back to ie if I wanted
and my most prized extensions:
InformEnter lets you setup profiles for field data entry (has saved me HOURS)
Tab Mix Plus extra tab options not found in the default firefox including saving tabs from last session
Spellbound full spellchecker for all content within html including forum posts and fields etc