Phantasy Star's a great game with tremendous replay value. Like Nemesis, I've probably played it a million times more than any other game this gen. It will occupy you, and consume your life as you know it.
If you don't want to get that involved, but want a deep experience, pick up either Skies of Arcadia or Star Fox. You could get Animal Crossing too, but it's more replay value like PSO. So, there's what you have.
And.. I honestly have no idea how the Sims would turn out.