[merlilot]

You have a computer-room copy? [img]smilies/biggrin.gif[/img] Sounds like a true die-hard fan there. [img]smilies/biggrin.gif[/img]

But seriously. I think he realized that he was the only one that both could and would. The Elves wouldn't have let the Dwarves take it, and vice versa, for obvious reasons. Neither of those races would let the Men have it, for obvious reasons. Elrond and Gandalf, whom all would probably have trusted, refused it, for obvious reasons. Bilbo and Frodo were the only ones left, and Bilbo couldn't go. So...
The Elf/Dwarf part is rather accentuated in the movie: he was the only one who could get near it besides Elrond and Gandalf and not get beat up.