I'm with daystar on this one. WTS doctrine is, after all, mostly based on their interpretation of scripture, so it could be seen both as "true" and "false" at the same time. It all depends on who you ask.
The thing that makes so many of their teachings "wrong" or at least "inappropriate" would be the effects that they have on the lives of JWs and other WTS adherents - no blood means death for a lot of people, especially minor children, no holiday celebrations means alienation from the rest of mainstrean Christian society, disfellowshipping means destroyed families, the list goes on. And the fact that they change their minds on certain doctrines, like changes to the rules regarding rape and blood fractions, makes the WTS and its doctrines even less credible. How can you believe an organization when they're not even sure what they believe??
So in my opinion, I believe that most of what they teach is wrong, though I'm sure that the faithful JWs out there will argue with me. I'll finish off this post with a movie quote that was used as a response to one of my threads a while back. It's regarding what you deem personally acceptable and appropriate, despite what you're told is right or wrong in God's eyes:
"God will understand, my lord. And if he doesn't, then he is not God and we need not worry." (Kingdom of Heaven, 2005)
-Becka :)