Snorbs you make some really interesting points. I'll bring some of my thinking to it, for what it's worth :)
springydaffs, what I mean is this: We are, apparantly, not worthy of salvation. We are being held to impossibly high standards and inevitably fail to reach them. We live in a world full of disease, parasites and natural disasters.
We're not being held to impossibly high standards, because through Jesus God has provided the means to be where we should be - in relationship with God. It's true we cannot hold up to the standards of holiness, but thank God, we don't have to and are completely free from having to strive towards any such goal. It's one of the many freedoms that comes with accepting what God's done.
Humans didn't create this state of affairs, god did. God created the standards to which we are held even though, as an omniscient being, he must presumably be aware that we cannot possibly meet them. God created the parasitical worms that burrow into the eyes of innocent children. Even if you believe in evolution rather than creation, again, an omniscient deity would know the outcome.
Classic Christian doctrine teaches that when humans decided to go their own way, ie against God, that not only did we fall but the whole of creation fell. There's a haunting passage in Romans which talks about creation groaning and waiting for its restoration. Parasitical worms and disease and natural disasters are the result of the whole of creation becoming skewed, becoming not as it was made to be. I know Satan, or the devil is a laughable image and not often talked about as it sounds nuts to even entertain the possibility of such a creature, but I believe the bible, and I believe there is this source of evil so hugely malevolent and vile that it's too simplistic to say 'it's humankinds fault that creation fell.' I believe the world being skewed and full of suffering is due to more than a man eating an apple 
- So yes, I believe God knew the outcome, and cries and hurts over it, through it and with all those who suffer as a result, over and over and over again. And sent Jesus to redress the balance.
Whether faith alone is enough for salvation depends on whether you regard James 2:20's "But wilt thou know, O vain man, that faith without works is dead?" as worth following or not. If faith in Jesus is the only thing you need to enter heaven then that leads us back to the question over what happens if you live in the Amazonian rain forest and have never heard of Jesus.
IMO faith should always be accompanied by deeds, and faith that isn't is not the kind of faith Jesus is requesting and modelling himself. If faith is true faith, deeds will be there. If not (as in the case of those who engage in wars, bigotry etc in the name of such) I don't believe it is there.
Interesting aside about the Amazonian thing - I have a friend who visited an obscure place in South America somewhere (hazy on details, I'm shit at remembering facts) and talked to a man who knew Jesus, but had never heard of Christianity. He recounted how he'd been searching for God, and had a dream and Jesus spoke to him. He knew Jesus was who he'd been searching for and came to a living faith which he'd passed on to others. I always think of this when people say 'what about those who have never heard' etc because as I said above, I reckon God has it sorted, I reckon God is just, I don't need to worry. However, your point then about 'what's the point of evangelism in that case' is highly valid and one I've thought a lot on. In the end I believe Jesus told us to tell others, and therefore I'm obeying (Matt 28), and that's enough. And within that I find something freed, something beautiful....I can't explain the whys and wherefores.
God set up the conditions that lead to the situation we find ourselves in today. The Bible makes it clear that we are wretched sinners unworthy of god's salvation. God does not actively help us to get out of this situation without us first having to jump through the hoops of believing a number of things about him on faith alone and/or living a life attempting to meet standards that we are incapable of meeting.
I think God did actively help us to get out of this situation, by sending Jesus to model a life of worship and perfection, to die in our place and conquer death. I reckon it's a pretty awesome way to get right in there with us.
So to put that into terms of me as a father relating to my children: As my children grow up I repeatedly tell them that they're never going to be good enough. I engineer situations in the full knowledge that my children will be harmed, and quite possibly killed, by those situations.
Or, as my children grow up they often rebel against me, perhaps in bigger ways as they get older. I always tell them I love them, whatever, and will always love them. Nothing they can do can ever stop me loving them with my entire being. I repeatedly tell them I delight in them and that they are beautiful. I hurt so much when they get put in positions of harm, of bullying, of danger, and I cry with them when they get hurt. If I can do anything to stop the hurt, I do it. Sometimes they walk right into situations and I cannot intervene. But I'm there for them and they can walk right into my arms at any time.
That is how I experience God.
All the time I demand of my children that, despite the appalling way I have treated them, they must love me with all their hearts and trust me implicitly otherwise I'll kick them out of the house.
I give them the choice to love me with all their hearts and to put their trust in me. They are welcome in my house at any time they ever wish.
At no point do I accept any personal responsibility - I do it because I love my kids so much! And, anyway, it's all fine because they have free will and after I kick them out of the house they can return any time they want provided they first accept that I love them and that they love me totally.
I do love my kids so much, and they do have a choice, and they can return anytime. I stretch out my arms to them even if they don't realise I love them and even if they don't love me.
That's something of where I am with it although I'm sure others will be along putting it much better. :)