Thorium is far more plentiful than Uranium. Thorium LFTR reactors are more difficult to weaponize (which is why they weren't initially adopted over current nuclear technology), and are far safer than standard Uranium / Water cooled reactors (basically 0 meltdown risk).
See http://www.youtube.com/watch?feature=player_embedded&v=uK367T7h6ZY for a good overview, and the comments to see the pluses and negatives of thorium technology. The US has plentiful thorium resources, and we should at the very least be starting a strategic reserve of the stuff.