This is a story of how even the smallest among us can make the biggest differences. It's a universal hero's journey where the hero, like always, can only triumph over his obstacles with the help of many allies, in this case elves, men, dwarves, etc. Cooperation, teamwork, good vs. evil -- it's all there.
Many of the Fellowship's skirmishes with the Ringwraiths, Orcs, and the rest of Sauron's Army are likely to frighten younger audiences. In Moria, the remains of the long-dead dwarves are shown (they're bones). Orcs are freaky looking, and the battle results in deaths. The combination of live-action and animation makes certain scenes seem all the more realistic, creating a creepier, scarier mood through the darker parts of the film.
The Hobbits stop at a pub where they and other characters drink what's presumably alcohol and some smoke pipes.