Sunset Valley is the town I know best, and it will always be special, because it was my first. I love Moonlight Falls, Lucky Palms, Monte Vista, Roaring Hights and Dragon Valley. Lunar Lakes reminds me (in a good way) of the wacky, low budget science fiction films of the 70s, I used to watch as a child. Sunlit Tides is just gorgeous, especially the lighting.
I don´t like Bridgeport, not just because I´m not that fond of big cities, but also because the routing is absolutely terrible. Barnacle Bay is a bit boring, Isla Paradiso drives me insane, because it´s so beautiful, but even with fixes it just lags.
Apaloosa Plains is a bit too spread out for my liking, Midnight Hollow is really interesting, but I never find anything, because it´s so dark. Aurora Skies is a bit bare (which is the point, I guess).
Riverview, Starlight Shores and Twinbrook are alright, but I don´t play much there.
As for CC worlds, I love the ones from Rflong. Right at the moment, I´m having a lot of fun in Cake Island II.
(And I just realized, the only store world I don´t have is Hidden Springs. Maybe I should do something about that.)