Mine is the spice district in San Myshuno, it's so colorful & has the basketball court for some outside activity. I always pick the 20 Culpepper House (Where the Rasoya household lives until I kick them out) for my sims to live in because it's spacious & has a perfect view of the festival area.
I also love Strangerville Plaza. It's about the most awesomely cool neighborhood ever created in any Sims game ever. And finally, the island in Windenburg, it's private & peaceful, or was until the evil leaf piles showed up & they needed random sims to play in them.