Which is the safe and convenient area to stay in Lisbon?

Hi I understand that the airport bus will alight at certain stops such as as Entrecampos, Campo Pequeno, Avenida da Republica, Saldanha, Picoas, Fontes Pereira Melo, Marquês de Pombal, Avenida da Libertade, Restauradores, Rossio, Praça do Comercio and Cais do Sodré. I will like to know which area should i book my stay without walking too far to search for my hotel after alighting from one of the stops. Pls advise which district in Lisbon is safe and convenient for tourists to travel around at ease? thanks for your valuable advise