Might be Cottage Living. It added so much, not only to the country side households.
I think CoL and Seasons might have been the only packs I positively bought on release day. Other packs were good also, but because the way I play my game, a new pack often comes while I'm busy with something else in-game or I'm expecting lag to get worse with a next install. This way I often get behind with a pack or two, and might discover jewels rather late. One example is Snowy Escape that I like a lot, but got this Winter. I was actually surprised that I did not get it earlier.