Well, the save that I'm currently playing, probably has the sims I most enjoy out of any I've ever played, but that's not the question.
I think the sim I remember the most was Bruno Laurel, mostly because he was a perfect, fashionable, outgoing actor, but he wasn't even one of his siblings I had the most fun playing, as I had a lot more fun with his sisters and their less perfect more relatable lives (One a struggling author, pregnant with her neighbors baby, and the other an insecure archeologist I related a lot too). I think the most memorable sims for me are the most outrageous and perfect ones, but they aren't necessarily the ones I had the most fun with.
Then of course there's Barbara Kreisner and Norma Geraldine, but I remember them mostly as in-jokes with my sister.