Well, my faith has taken some knocks recently, but essentially, I believe in one God who exists in three persons, Father, Son and Holy Spirit. I believe Jesus died an atoning death for the sins of people who were His enemies. That's not what makes me a Christian, though, what does that is trusting that my sins were among those He died for.
Hell is a nasty, dreadful proposition, but so is sin, and I can't gloss over sin (no matter how much I try), so I can't really gloss over hell. I don't believe the idea that it's 'separation from God' alone suffices, either, because most of the people I know who don't even believe in God don't really find that a particularly compelling notion of punishment, really. And I do think the idea of hell is fundamentally an idea of punishment.
Of course, that all assumes a certain view of God himself, which is where Christians often disagree.
So basically, I believe in a God who is so holy and perfect He can't even look at sin. But because He is perfect, He is also love, and in that love, chose to take his absolutely appropriate anger about sin, and make a way to blot it out entirely for his people.
And Christians don't get to boast and point their fingers at other people's sins, because they are not one teensy weensy bit better than anyone else, and every bit of forgiveness and grace they have are freely offered to anyone who will have them too.
I don't know, maybe I've made it sound far too complicated, and if I have, I'm sorry about that.
But really, you can go round the houses wondering about sexual mores and other religions and so on, but that's the core of it - grace, free forgiveness offered to wicked people who really don't deserve it.