Earthbound would have to be mine. I played a few RPGs before that one but that's the one that started my real love of the genre. My parents bought it for me without having a clue what it was. Luckiest purchase ever. I played it probably 30 times all the way through and my Alarm Clock actually uses the song from that game after you wake up from sleeping in a hotel.
After that would be the games that I think are beutiful and changed what I thought about the artistry of games like SotC and Flower.
Predecessor, but the sentiment is the same.
Play Mother 3?
Well I got Mother 3 when the translation came out, but I couldn't get into playing the game on computer without a controller. Weird considering how much I love Mother 2 but it didn't seem worth the effort to go out and buy a controller for my computer for a single game.