Well, technically she was in all of the episodes, but I know you're meaning Stephanie-centered/related episodes.

I agree with both of you, especially about her clinginess in Aftershocks. I think pretty much all of my top 5 episodes are Stephanie-centered, except maybe for Rock the Cradle.
Anyways, some great Stephanie episodes that I think of...
"Aftershocks", Honey, I Broke The House", "I'm Not DJ", "Silence Is Not Golden", "Middle Age Crazy", "Spellbound", "Fast Friends", and more I'm sure I'm not thinking of.