Here is a breakdown of the different areas in and around Bariloche:

Downtown - "El Centro". 50 years ago, downtown Bariloche had the charm of a small mountain village.  In recent years the construction boom has turned it in to a small city with numerous restaurants, clubs, bars, casinos, shops, and government buildings.  Definitly worth exploring, but if you're looking for nature and great views you may want to stay outside the downtown area.

"Los kilometros" - To the west of the city, this area is mostly residential and almost everything is within a few blocks of the lake.  Quieter and cheaper than downtown.  Best places have great views of the lake and surrounding mountains.

Cerro Catedral - The ski center.  Fairly expensive compared to other locations, but allows easy access to the slopes in winter and numerous hiking opportunities in summer.

Llao Llao - The hotel that made Bariloche famous is located on an isthmus between Lakes Moreno and Nahuel Huapi.  The area has beautiful vegetation and native forests, with upper end options for dining and lodging.  Located on the "Circuito Chico".

"Circuito Chico" - One of the most popular day trips, it is also an ideal place to stay if you are seeking nature, quiet, and proximity to lakes Moreno, Trebol, or Nahuel Huapi. Highly recommended if you have your own transportation.

Road to El Bolson - Goes past the Gutierrez Lake south of Bariloche and is the first leg of the journey to Pampa Linda and the Tronador glacier.  Popular with fishing activists and nature enthusiasts.