If you're planning your first trip to the ‘Big Mango’, then chances are you're wrestling with the issue of where to stay. If you're not tied to a specific chain - and they're all present, often with many properties around the city - then you're most likely faced with the challenge of which part of the city to stay in. The decision usually boils down to two main choices: the riverside or the central shopping area stretching from Siam Square down to Asoke.
The argument for the Riverside is hard to resist: It can be cooler near the river, and no matter where you come from, Bangkok is probably going to be hotter than you're used to. The scene of life on and near the Chaophraya River is also distinctly Thai. All you have to do is look out the window to be reminded you're in a foreign country. Proponents of a more central area like being close to so many restaurant and shopping options.
There is a common denominator to both locations: convenient transportation options. Bangkok can be a difficult city to navigate for independent travelers, but if you familiarize yourself with the train and boat system, and choose a hotel near them, then you'll easily make your way around the city's sights on your own, without having to deal with taxi drivers who don't speak English or tuk-tuks who try to scam you.
The Thai capital is most travelers' entry point to Thailand. Most foreign airlines only fly into Bangkok, although if you are coming from elsewhere in Asia, some flights are available directly to places such as Phuket and Chiang Mai. In recent years there has been some tendency to bypass Bangkok or move on up-country quickly due to the city's notoriously bad traffic.
In fact, traffic is not as bad as it used to be and there are many places worth seeing in the big city. Almost all of the most interesting sights are near the river, and so accessible by express boat. Between the boat and the train system you should be able to get just about anywhere in town that a tourist would want to go. Pick your hotel carefully to be near the river or the train system, and you'll have no trouble getting around on your own.
The "standard" tourist sights include the Grand Palace in which the temple of the Emerald Buddha is located and the nearby temple commonly known as Wat Po where the large Reclining Buddha is found. Tour groups are also often taken to see the large solid gold buddha in the otherwise unremarkable Wat Traimit.
If you're on your own or in a small group, we highly recommend a tour of the canals by long tailed boat. Its the best way to cool off after a hot day trudging around a few temples. Most riverside hotels rent boats, or you can arrange them from the pier at the River City shopping complex. You generally pay by the hour. Two hours is more than enough to get a flavor of canal life, see the royal barges and stop by Wat Arun.
For more ideas about what to see and do, as well as where to stay and eat, see my lists of the best of Bangkok.