The Elder Scrolls and The Sims: My "Favorites"

Admit it: Every gamer has his or her "Favorites". Despite how you say you like all the games in your collection, you probably have a few that you'd, for instance, grab first in the event of a fire. My two favorites happen to both be for the PC. I love Morrowind, the third in the Elder Scrolls Series, and The Sims 2. Because of this, I'm hoping to buy an expansion pack for the Sims tomorrow. On Thursday, I'll be getting Oblivion, the "sequel" to Morrowind.

My questions to you are: 1. What are your favorite games?
2. What expansion pack do you recommend I buy tomorrow? I really like all of them and can't choose.

P.S. Fellow gamers waiting for Oblivion, take heart: I will post a review of it as soon as I can.