Often it is hard to come to a new city and decide where to live. If you don't have a local friend to guide you, you can end up too far away from your job or area of the city that excites you. For Ankara, here are a few choices:
Cankaya/Ayranci: These two areas are closely connected, with Cankaya being furthur away from the downtown but still easily accessible (15-20 min by bus). These areas are inhabited by families, young professionals and older couples. There is a great mix, although the night life and shopping is less dense than places like Kizilay. These areas are very much more residential. That being said, you can find a medium priced furnished aparment here at around 700-800TL. This area is quieter than being right downtown and is up the hill a little bit which makes it a bit fresher.
Gaziosmanpasa: This is a popular area for foreigners who are working in Ankara for embassies and political reasons. It is furthur out of the downtown than Cankaya, but is still easily accessible by bus and dolmus (30 min). Again, the shopping and night life is less dense than in the downtown but the area is more residential and quieter. Gaziosmanpasa is close to Oran as well, and a nice apartment in these areas has the potential for great views. Apartments in Oran that are furthur out can take up to 45-50 min to get to by bus from Kizilay.
Dimirtepe and Maltepe: Both are older residential areas and are only a 5-10 min walk to the Kizilay area. The areas are less populated by expats, but are more convenient than Ayranci or Cankaya. Good accesibility by dolmus and bus.
Bahcevler: Baclevlier is somewhat near the Ataturk mausoleum, to give you an idea of its whereabouts in Ankara. This area is fun for restaurants, bars and shopping as it full of students but also people from all walks of life--families, young people etc. This area is pretty with trees lining the streets and great shops. It is easily accessible by the Metro, which is a bonus. It means you can conveniently take the train to all areas of the downtown Ataturk Blvd core within 20 min.
Kizilay: Kizilay is a great place for cheap eats, low-high priced shopping, student culture, bars and night-life. It is always filled with people and is mostly made up of pedestrian streets which creates a great atmosphere. Some people feel that living too close to the main Kizilay area is too noisy; or lament that everything closes up too early. Although the noise might be a problem, night markets show up at night and bars stay open fairly late. If you are looking to be in the middle of it all, Kizilay might be a good choice.
TunalI: TunalI is a great area if you are working in embassies or enjoy a ritzier area. Books like Lonely Planet comment that "if you want to see how the rich Turks live, go to TunalI", but this is misleading. TunalI has small indoor pockets of stores, as well as nice bars and restaurants that are reasonably priced. There is however many coffee bars, stores and restaurants there that can be very expensive. If you are looking for imported goods, TunalI is a good place to look with a Mango, Marks and Spencers, Banana Republic and D&R bookstore. TunalI apartments will be a little pricer, but not out of range for most people. One problem is that it is not always conveniently accessible by Dolmus or bus; unless you are living close to main streets.
Ulus and the Citadel: These areas are the oldest areas in Ankara, complete with Ottoman housing on the citadel. It would be cheap to live in this area, but women may not feel comfortable going out at night alone. The crime rate is a little higher here than other areas due to poverty. The kale, or citadel, has grown in popularity but is not appropriate for foreigners to live in unless they are willing to buy and restore an Ottoman house. Otherwise, Ulus is a great place to visit for the markets and the great restaurants on the citadel. Accessible by Metro.