There are several great areas to stay in Bangkok, where you can easily connect to the famous sightseeings and attractions. The accommodation type is varied across the areas which could range from a cheap hostel to a 5-star luxury hotel. BTS and MRT are the most common transportation channels to travel inside the city, and taxis are also available for the most areas with the affordable price.
The center of the backpack traveller, Khao san road is a popular place for travelers, especially for the backpacker, where tons of street foods, pubs and bars are available for the whole night. Several great budget hostels are available in Khao San area, or there are also tons of mid-range hotels available in this area too. There is no BTS or MRT near Khao san that you can walk to, but you can travel by Taxi or tuk tuk instead. The Chao Phraya express boat is another great choice of transportation channel, where you can take the boat at Tha Phra Arthit to an attraction along the Chao Phraya river.
Siam is the center of the shopping center, where you can find anything you want in this area, such as luxury brands, restaurants, cinemas, massages etc. You can also travel along Bangkok by BTS at the Siam station. Siam is a very busy district in Bangkok, so the price of accommodation in this area would be slightly higher than others.
Yaowarat or Chinatown is the hippest area to stay in Bangkok, where you can sense the oldest town in Bangkok. Yaowarat is much well-known for its night street food where you can get plenty of cheap and great street food after 6 pm. You can also get to the MRT from the MRT Wat Mangkorn, the nearest MRT station from the center of Chinatown.
Silom is one of the busy business districts of Bangkok, so you may see lots of accommodation in this area. In addition, Patpong, the popular nightlife area in Silom, also draws more attention from tourists to this area. There are lots of pubs, bars and many restaurants available for you in every area in Silom. You can also get to both MRT and BTS at BTS Saladaeng and MRT Silom, which ease your transportation.
You would see lots of foreigners in the Sukhumvit area, when lots of foreigners who work in Bangkok choose to stay in the Sukhumvit area. There are plenty of luxury hotels, shopping malls, pubs, bars and restaurants, especially for luxury clubs, pubs and bars where you can find it easily in Sukhumvit area. You can also access to BTS easily along the Sukhumvit line and MRT from the Sukhumvit Station.