Probably FFVI, I had not played a turn based RPG since Battletech on PC, and by that time in my life, I was pretty hardcore into fighting and action games. I hated it initially, though I was interested in the story, but it wasn't until Secret of Mana made me want to expand my horizons into the RPG genre that I came back to it and fell in love.

Threads of Fate was another one, the demo I had for it was cute but not really "must buy" but a friend bought it for me for my birthday and getting far into t made me realize how it was the spiritual successor to Brave Fencer Musashi.

Suikoden was another, while a review made me intrigued by it enough to borrow it from a friend, the first half hour of the game isn't exactly "amazing", but I muscled through and came to fall in love with the game and the series as a whole.

I can't think of anything other than that, most of the time I'm usually surprised by finally playing a game that has a lot of hype only to be pleasantly surprised it lives up to it.