I miss some of the EP's, especially University. I played that for a little bit a few days ago, and loved it. I also kind of miss the lack of Story Progression. I liked not needing to monitor if my other Sims had moved out, etc etc etc. From TS1, one of the things I will not miss will be the cheats. I remember having to type "kaching;!;!;!;!;!;!;!;!;!" to get $10,000. And the Motive Maxing cheat was the worst. You had to delete your Sim with MOO, then click on their sim-panel portrait, which would bring them back. But you had to save first or stuff like Skill Points gained would be lost.
I miss the memories. I know TS3 has Memories, but they're not like the TS2 memories. In TS3 you get memories for stuff like going to the park. In TS2, you got memories for Very First WooHoo, First Kiss, Marriage, Maxing Skills...