For Expats in Lisbon, there are all kinds of great options to choose from when picking a neighborhood, or neighborhoods to explore, as great options to have near where you'll live. Some people elect to live near the city center, while others choose the outskirts and rely on public transportation to dip into the action from time-to-time.
Benfica contains Monsanto Forest Park, which is the largest forest park in Lisbon. The public transportation is good and there are some colleges in or near Benfica. Relatively affordable housing can be found here because it is a bit removed from the city center.
Chiado is widely regarded as a great shopping area, and it has its attractions, such as the Cafe A Brasileira and the Chiado Museum. It is not an inexpensive place to live, but it has excellent public transportation and offers plenty in terms of entertainment, history and commerce. Here are a few other things to do in Chiado.
Avenida da Liberdade
Avenida_da_Liberdade is in central Lisbon and is thought of not as a place to live (i.e. not a ton of housing on it), but a place to visit for things to do, such as high-end shopping. If someone says "the avenue," this is the place. It has meticulously maintained park space and monuments, and visitors will find excellent hotels on or near Avenida. Principo Real, Chiado and Baixa all border and are considerations to live near Avenida da Liberdade.
The are plenty of things to do on Avenida da Liberdade, as restaurants, cafes and theaters attract many to this part of the city.
This district with a suburban feel is seeing significant development. An article about Lisbon on FT.com noted that "Portuguese fashion designers, architects and advertising agencies are based [in Principe Real], and there are quirky boutiques and upmarket antique stores alongside local bakeries, grocers and cafes."
Restelo is perfect for anyone looking for a quieter area with more room. Located next to Belem, it is on the western side of Lisbon. It also has the Estadio do Restelo, which is home to C.F. Os Belenenses and a venue for major music concerts.