I found the following article on bangkok.com via Google. It's quite interesting...
"To most Thai people, Bangkok is much more commonly known as Krung Thep, which translates roughly to 'City of Angels'. And, just to disorientate you further, Krung Thep is only the abbreviated version of the capital's full ceremonial name, which has made it into the Guiness Book of Records as the longest place name in the world!
While rarely used in everyday life, apart from a few signs aimed at tourists scattered around town, many Thai people pride themselves on being able to recite the entire name by heart. This is usually down to a 1980's rock duo, Utsanee Wasun, who deftly worked the name into a catchy song.
The English transliteration reads:
Krung Thep Mahanakhon Amon Rattanakosin Mahinthara Ayuthaya Mahadilok Phop Noppharat Ratchathani Burirom Udomratchaniwet Mahasathan Amon Piman Awatan Sathit Sakkathattiya Witsanukam Prasit.
Which translates into the following long line of superlatives:
The city of angels, the great city, the residence of the Emerald Buddha, the impregnable city (of Ayutthaya) of God Indra, the grand capital of the world endowed with nine precious gems, the happy city, abounding in an enormous Royal Palace that resembles the heavenly abode where reigns the reincarnated god, a city given by Indra and built by Vishnukarn."