I'm hooked on The Sims as well (the original versions, not Sims 2). However, for PC gamming, it runs close with Armed and Dangerous by LucasArts. You just can't go wrong with the Shark Gun!
Platform games....that would have to be either the Lego series (Star Wars, Indiana Jones, Batman) or the Medal of Honor series. One for fun and laughs -- the other for basically filling my reenacting needs when it's too crappy to go out in the field.
Guilty Pleasure: Automobile of your dreams