My dear Purposedriven,
I wander if you know that...by becoming a Muslim, you will love, respect, and follow the teachings of Jesus Christ (peace be upon him) more than if you were a Christian. Being a Muslim requires you to develop more love for Jesus (peace be upon him). The things that you will have to give up in terms of belief regarding him, are things that he never preached, i.e. the belief that he is divine, is son of God, died for our sins, or was crucified.
By becoming a Muslim, you are actually following the true teachings of Christ (peace be upon him). He never made pork lawful for his followers to eat. He never told people to worship him nor did he say he was God. You will be following the faith that all the prophets (peace be upon them) preached.
We believe in all the prophets, from Adam, right through to Muhammad (peace be upon them all). They didn't preach different faiths, but said to people "Worship Allah, my Lord and your Lord, and associate none in His divinity."
We do not reject any of the prophets (peace be upon them), neither do we exaggerate the status of any of them to something it wasn't.
Of course you will have to follow the teachings of the last Prophet Muhammad (peace be upon him), who came confirming the earlier original scriptures.
I found the following EXCELLENT link which gives commands that are common between the Qur'an and the Bible (such as abstaining from pork, alcohol, women covering themselves, prayers and washing before prayer, Jesus peace be upon him not being divine etc etc), which Muslims follow and Christians don't, and it gives you all the Biblical (and Qur'anic) references to back it up.
http://www.irf.net/index.php?option=...128&Itemid=146
Various issues are discussed and then the conclusion is reached that, actually, Muslims are more Christian than the Christians themselves! All because they are following the unadulterated teachings of Christ (peace be upon him). But it's explained in a nice, non-condescending and non-patronising way.
The video of the talk that the above link came from (Similarities between Islam and Christianity) is here:
http://www.archive.org/details/21_Si...ity_truthwaytv
With regards to putting up a Christmas tree, I can understand thats its something you've done for so long and is so part of Christmas and that time of year for you. But I think that they were originally of pre-Christian, pagan origin. A true love and obedience of Jesus's commands (peace be upon him) will be more beautiful in the sight of God than a tree, no matter how nicely it's decorated.
http://en.wikipedia.org/wiki/Christmas_tree
We have a chapter in the Qur'an named after lady Mary (peace be upon her), and Jesus (peace be upon him) is mentioned by name in the Qur'an five times more than prophet Muhammad (peace be upon him)
Sister, I know it's probably easy for me to say, but please don't feel spiritually torn. I would say, please look at the links over the next few days/weeks, objectively. See it as a fact finding mission that you are going on. And just for that next few days/weeks, put that torn feeling aside and look at the facts. At the end of that see how you feel.
Oh and of course, make earnest prayer to God to help you and guide you.
With very best wishes for you. :)
May Allah guide you (and us all) to the straight path. Ameen.
Peace.
P.S. Also, if you have any other questions or doubts, please ask :)