Super Mario RPG absolutely was my gateway into RPGs. I read Nintendo Power's coverage of Final Fantasy 3/6 and stuff in the Epic Center, and the games seemed way too complicated for me. Also, the idea of a turn-based battle system sounded impossibly dull.
My Blockbuster had a deal where if you rented Tetris Attack, you could rent another game for free. So I got Tetris Attack (which I wanted anyway), and for my free game, I took a flyer on Super Mario RPG rental.
I was immediately hooked on the genre I'd ignored for so long.