It depends on the story and aesthetic that I have in mind when I start a new family & house. I'm currently in love with the CL world (Henford on Bagley? - I have trouble remembering the names of the worlds and neighbourhoods). The Bramblewood is my favourite, but the town is useful for quick trips to the grocers. I do like larger neighbourhoods that have some added features: collectible spawners and plants, the shops in Henford, the hiking trails in Mt Korebi.
I still like Glimmerbrook and Mt Korebi, and I wish we could live in Granite Falls. If I don't care about snow, Oasis Springs is still a favourite.
It's easier to say which ones I don't use. Strangerville not much, because there are few convenient fishing spots (though this is less important now that we can build our own ponds). I like Sulani, but I don't like most of the lots for building, and the university world (name?) only has one tiny buildable lot. Same with San Myoshuno - I've only used that once. I don't even visit San Myoshuno. Newburg is rather soulless, and Willow Springs is a bit tired. I don't really care for Evergreen Harbor, though I've played it a bit.