I have played a lot of the classic games with my friends, years ago. Firts, D&D, then MIdgard, later Fading Suns (The game the Stargate series was ripped of, the creators decided not to sue), Warhammer, you name it.
D&D is, to me, the ultimate starter pack.
Later - well, where you want to go? medieval, sci-fi, gore, there is so much around.
To me, I best liked Warhammer. The writers were very tongue in cheek and we played an adventure agains a demon called 'Zahnarzt' (German for: Dentist) who was to, like evil superpowers do, enslave the world
Go for that, later, when you got the concept of roleplaying working. Because, really, the fun is in the creating a role and really acting and walking+talking in it.
Everone can go and slay monsters and save princesses, but it takes some extra work to build a role