I know I'm seriously off-topic, but I can't sit aside without weighing in on this conversation a bit. Allow me, a Muslim, to step in on this, if I may:
fair enough and Gengis han let you live and go about your relegion but slaughtered you if you opposed him.
Luckily for us, the Muslims were much more civilized that the Mongols. Citizens in cities taken over by Muslims were given three choices: leave, stay and become citizens and pay the tax (which I discuss below), or continue to fight. This as compared to your Mongols who gave no quarter regardless of the situation, or even as compared to what Christians did during the Spanish Inquisition and the Crusades.
1. The Muslims regularily taxed Christians for their faith
Yes. However, people fail to realize that Muslims were "taxed" in the same fashion and at the same amount: 2.5% of one's earnings per year, except it's called Zakat for Muslims and Jizya for non-Muslims. This "tax" as you put it was obligatory on most people -- Christian, Muslim, Jew, etc. -- living in the Muslim State, save for a few exceptions (e.g., orphans, widows, the aged, etc. Anyone considered to be a ward of the State did not have to pay and instead received money). The tax went to help care and feed said wards of the State, including non-Muslims. Yes, that's right: if you were a non-Muslim in Muslim Spain, you could count on the State to support you if you were unable to work. There's even a famous Hadith about this.
2. Converting to the Christian faith (from a Mulsim) is punishable by death
The only basis for that ruling that I've found was a judicial ruling dating back to the 11th and 12th centuries, during the Crusades, you'll note. The premise was that yes, if a Muslim converted and was still on Muslim soil, he was guilty of treason to the state. Seeing as how Muslims and Christians were in the Until recently, no one has challenged that ruling. However, in the past few years, as Islam comes out of its religious lethargy, several graduates of Al-Azhar Mosque in Cairo have insisted that, since there is no compulsion in religion, Muslims may freely convert.
3. Mulsim man marying a Christian Woman is OK so long as kids are Mulsim
4. Mulsim woman marying a Christian man is punishable by death ...
I will not argue that what you point out in point 4 does not occur. However, you should realize it is not part of Islam at all. It's a tragic consequence of fundamentalism and a gross misinterpretation of the religion.
Throughout the life of the Prophet, Muslim women found themselves married to people who had yet to convert. This did not incur and immediate divorce or an immediate death sentence. Instead, the Prophet advised these women to have patience and to encourage their husbands to accept Islam for as long as they were able.
Any Muslim is free to marry whomever he or she wants. Muslims are heavily encouraged to marry other Muslims because it makes family life much easier to handle, but they are free to choose as they see fit. Indeed, there are two Muslim men in my mosque who have married non-Muslims, and there is one Muslim woman who married a non-Muslim man, though admittedly the man later converted.