Ugh, it may sound weird but my favorite world is Riverview. I don't know why, maybe because it's simple and peaceful. I don't have all the EPs + I've never bought a Store world, but Riverview is just the best of these I already have :)
I like also Appaloosa Plains, although I don't like how the dog park and cat park look like. Twinbrook is just okay.
Bridgeport isn't my favorite because (in my humble opinion) it looks dark and gloomy. Paradise Island is beautiful, but only in spring and summer. Falling leaves and snow just don't match to this tropical world.