Phantasy Star, it was the only RPG of it's kind. Most RPGs of it's time took place in medival times where you slayed dragons and explored caves and dungeons. This game was pretty much a combination of Sci-Fi and fantasy, almost like Star Wars, only with more plot twists. That's why PS is the best RPG series ever, DOWN WITH SE UP WITH SEGA.

In fact, everything Sega has ever made was innovative.