God loves everyone... Even dictators? God loves all humans, but does his love have limits? Can God love a person like Adolf Hitler, who killed millions of people who believed in him? What about serial murderers? Could God forgive a person like Hitler, if he was to come to faith?
ericgorr's answer is really good, but let me write a slightly simpler one.

Yes, absolutely God does love everyone. He totally wants the best for them and wants them to be the perfect person they were intended to be.

Now the trouble is that for Hitler, being the best he was intended to be absolutely involves not killing millions of people and starting a huge war. So God really really wants him to stop doing that - and not just because millions of people are dying, but also because doing this is screwing up Hitler as well and turning him into something he wasn't meant to be. Because of this God hates all the things that Hitler is doing, but still loves Hitler himself. Christians say that God "hates the sin but loves the sinner".

So let's imagine that in 1945 Hitler, instead of killing himself in a bunker, realises that he has been doing entirely the wrong thing this whole time, and is really sorry and genuinely wishes he had never done all those bad things, and asks God for forgiveness. Christians call that repentence. It's as vital to the process of getting right with God as 'coming to faith' is. Because God loves him, and because of Christ's death, God would forgive Hitler. That's pretty fundamental to Christianity.

Forgiveness doesn't mean there are no consequences. Had Hitler repented and lived he would probably still have been tried for war crimes, would certainly have been punished and hated by many people, would probably have been executed. Some Christians believe he might have spent a long time after death in a place called purgatory before going to heaven, possibly to get over the horror of understanding what he had done. Repentance is not an 'easy way out' like a get-out-of-jail-free card. And doing bad things and planning to repent afterwards doesn't work, because that means you thought the things you were doing weren't really bad after all.

There you go. I hope that's a helpful alternative to the more complete answer.