Why is Bilbo Baggins an unusual hobbit?

He likes his supper, his pipe, and all the comforts of home.

Part of him is interested in having adventures.

He has been on quests with dwarves and wizards.

He is "as fierce as a dragon in a pinch."

He has been on quests with dwarves and dragons.

Explanation:

Bilbo Baggins is not at all an ordinary hobbit. He is both well-off, accustomed to the comforts of home, and slightly interested in having adventures. However, what really sets him apart from other hobbits is the fact that he has been on quests with dwarves and wizards.

Bilbo's Took relatives were prone to going on adventures, but Bilbo himself had never had to chance and was respected in Hobbiton before his adventures with Gandalf.