Ah yes. The classic "if you don't believe x you're doomed" argument. Because that always works.
Oh. man, the Mormon view on this is somewhat complicated, but I'll do my best.
1 Corinthians 15:22:
See the word "all" in there? Yup. We don't believe everyone who's not Mormon is automatically going to burn in hell for all eternity. Rather...
1 Corinthians 15:40-41
Everyone gets resurrected. Whether or not you make it to the Celestial, Terrestrial, or Telestial Kingdom is an entirely different matter. And only the most terrible of people (such as Cain, IIRC) end up in Outer Darknes, aka Perdition, aka Hell.
...I probably botched that. But basically, that's it, if any of my Mormon friends wish to correct me, go ahead.
And I'm not trying to preach, just trying to explain what I believe.