First, let me say that I have, as of yet, to understand the significance and necessity of believing in the "Trinity". As such, I cannot and do not defend or refute it in anyway. I have asked some "Trinitarian" friends to explain to me the importance of such a belief, but that simple and honest question has stumped them.
However, that being said, I do understand the utmost importance of believing that Jesus is God. JW (and LDS) put forward that believing in Christ is necessary for salvation but that He is not God. Others, such as myself, agree that faith in Christ is necessary for salvation, but disagree on who they say Jesus is. We cannot both be right. One of us is believing in a Jesus who does not exist! He is either God or He is not. If He is not God, then I need to be shown this because the Jesus that I believe has saved me does not exist! And if my Savior is non-existent, so is my salvation non-existent. This is the most important precept of the Christian faith and without it everything else falls apart.
Keep in mind that when we attempt to show why Jesus is, or is not, God (sola Scriptura), we need to take all of Scripture into account and not just those portions that seem to prove our point. Furthermore, we cannot take the explanations of another in order to defend our position. If we cannot defend our position from our own understanding of the Bible, then we need to shut up until we are able to do so. Because if we don't understand it ourselves in a way that allows us to defend and confirm our position, then who are we to say what we believe?
(Not sure what the character limit is for these posts, so I'll end this one and start another.)