First I'd like to point out that almost everyone on here are ex-JW's.
Secondly, if you are familiar with their errors already, heres some more ammo for your neighborhood JWs:
The word [OTHER] in Colossians 1 in not there in the greek at all-- JW's panel of under 10 people that didn't know Greek, Hebrew or Armaic translated the NWT themselves and changed a lot--including adding the word [other] so they could screw up the meaning of the verses. I'm not making this up :) - check the intro or whatever to their 'bible' and it will tell you anything in 's is inserted to help the passage "make sense". Try taking the word [other] out and see what the verse seems to say.
"He is the image of the invisible God, the Firstborn over all creation. For by him all things were created: things in heaven and things on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things were created by him and for him. He is before all thing, and in him all things hold together."
(sorry it's NIV instead of NWT but their 'bible' is in my cults research box at the moment :))
For further info on this you can e-mail :)