"I live on Oxford Street" is grammatically correct, because it gives your position as on top of or above a surface, such as the sidewalk or street of Oxford street. "In" is used for giving a position when enclosed or inside of a place, like inside the room, cafe, or house.

"I live on Oxford Street." Is propper. The use of prepositions in English is frequently idiomatic. General guidelines exist, but be prepared to learn individual expressions in which the preposition does not adhere to the guidelines. In the case of the prepositions in and on, here are the most usual uses. In in mainly denotes “rest at”: PLACE: He lives in the country. He lives in Chicago. (BUT, He lives at 2300 Wabash Ave.) TIME: I’ll be there in an hour. MANNER: The child ran down the steps in tears. REFERENCE: In my opinion we need a referendum. They are happy in their marriage. On on indicates proximity and position above or outside: PLACE: He sat on the fence. TIME: He was not thinking well on that occasion. REFERENCE: He asked my opinion on the matter. CONDITION: We’ll hire him on your recommendation. The examples given in the question: We are on the planet. We are going to the concert on July 1. But We are going to the concert in July. As for the example about the boat, either is correct, according to what is meant: The boat is in the water. (As opposed to being on dry land for the winter) The boat is on the water. (Look at all those boats out there on the water!)

It would be, "I live on Oxford Street" as you cannot live inside of a street. You can live inside of a place however, so "I live in Oxford" would be correct.

Edited: wrong answer.