First of all, you can believe it is not a play on words, but if this were the case why was it not always called "Islam"? Second I do submit to God, I will do anything he asks of me without question, the difference here is I am not Muslim and just as you do not accept my views as a Christian, I dont have to believe that Muhammad was the last prophet or a prophet at all for that matter.
It was Islaam because it was submission towards God, thats what all the prophets called to.

So anyone who submitted was a muslim. And you do have to accept Muhammad (peace be upon him) the same way the jews needed to accept Jesus. It's not a pick and mix, but we take the whole package.
Yes and they are called Christians, not Muslims
Maybe you could prove that with some evidence?
Being a Christian I believe in Jesus's word and he did not mention (as far as I know) that there was to be another prophet, in fact I believe he said that he would return for the end of days. So why would I listen to what Muhammad said?
We also believe he will return on the end days and slay the anti-christ. Jesus is the messiah and the part in the bible when it says that there will be others claiming to be false messiah's is true, because the anti-christ will also claim to be a messiah. Muhammad (peace be upon him) never was the messiah, because that was Jesus son of Mary (peace be upon them.)
If there were all of the prophets, then why is there so much evidence that people worshipped nature and other idols?
That's the catch. All other ways of life associate partners with God whether these partners are stone idols, or man made systems. So God sends messengers to call people to the obedience of God instead of worshipping man made objects [idols, laws etc.] That's why you hear so much controversy about muslims not wanting to vote in man made laws and philosophies.
Also, shirk which is the most heinous of sins in islaam doesn't simply mean to reject the fact that God exists. But shirk is to associate partners with God, and this is how satan decieved the people to believe that they should pray to a stone idol, to a pious human [i.e. a saint] in order to connect with God, yet God is the All Hearing so why doesn't the person pray to Him alone? This is where the majority of mankind has deviated, because their forefathers did this. The forefathers who disobeyed the Messenger of God.
Also why would the Quran and the Bible not mention all of them? Are they all not equally important?
Because there are 124,000 prophets as stated by the Messenger of God, Muhammad (peace be upon them.) And there's no real reason to mention all of them and God only relates to us the stories of those prophets which may affect our lives. I.e. Prophet Noah for his patience, Prophet Abraham for his sacrifices, Prophet Joseph as an example for the youth, Prophet Moses for his striving hard with his people to gain their freedom, Prophet Jesus in his patience when there were so much enemies against him etc. All the prophets are an example for us. So God relates to us the stories through His final messenger (peace be upon him.)
Steve is someone who replied above, and this is what I disagree with and the reason I started this thread. Thank you for your response
Brother ibnabdulHakim already stated earlier that those who never recieved the message will be trialled on the day of resurrection to see if they are worthy of paradise or not.
However, those who recieve the message clearly and still turn away are liable to God's punishment - as they had the chance to submit to God but they chose to turn away.
And God knows best.
Regards.