He/She asked about Rio, so despite my preferences, Rio it is ....Â
Santa Teresa. Every Carioca raves it as the consummate quaint neighborhood.
Lapa. ( bohemiam , close to old downtown. exquisite curbside appeal.
Botafogo. |it's posh. A lot of financial business are located there
Downtown ( Centro ) - it's coming along. still, a place for Urban Adventurers. There were some serious money being poured there for commercial redevelopment. A number of office buildings might be ripe for repurposing.
Urca ( with some luck, that is an exclusive enclave, no tourists around). I've been told there's a private beach around, which is the exclusive domain of military personnel, so access is only granted with pass. You will need some pull there. So no tourists there. No tourists = safer.Â
Jardim Botânico - It's between Leblon ( shoreline ), and the way towards Christ the Redeemer. The Botanic Gardens, this going back to my teenager days when I| visited Rio, actually soothes the Summer Dog Days of Heat . It feels cooler in the Botanic Garden vicinity than the rest of Rio.
Laranjeiras.  Not much I can say.Â
Breaking down on places you don't need a car...
Downtown
Bairro Imperial de São Cristóvão • Benfica • Caju • Catumbi • Centro • Cidade Nova • Estácio • Gamboa • Lapa • Mangueira • Paquetá • Rio Comprido • Santa Teresa • Santo Cristo • Saúde • Vasco da Gama
Favorites : Paqueta, Lapa, Centro, Santa Teresa
South (old posh )
Botafogo • Catete • Copacabana • Cosme Velho • Flamengo • Gávea • Glória • Humaitá • Ipanema • Jardim Botânico • Lagoa • Laranjeiras • Leblon • Leme • São Conrado • Urca
Favorites: Botafogo ( it's posh ), Gávea,Glória, Jardim Botânico ( it's past Leblon by the way towards the Christ Redeemer Status ),Laranjeiras. Copacabana and Ipanema are by the coastline, so only apartments.
West ( Working Class )
Bangu • Campo dos Afonsos • Deodoro • Gericinó • Jabour • Magalhães Bastos • Padre Miguel • Realengo • SantÃssimo • Senador Camará • Vila Kennedy • Vila Militar Â
Favorites : Up to Realengo fine.
Tijuca
Alto da Boa Vista • Andaraà • Grajaú • Maracanã • Praça da Bandeira • Tijuca • Vila Isabel
The Whole Tijuca is decent.
North Side
Bonsucesso • Bancários • Cacuia • Cidade Universitária • Cocotá • Freguesia • Galeão • Jardim Carioca • Jardim Guanabara • Moneró • Olaria • Pitangueiras • Portuguesa • Praia da Bandeira • Ramos • Ribeira • Tauá • Zumbi
Bonsucesso, Olaria, Madureira • Marechal Hermes