Update: One my recent visit (August 2016) I could not find the fast track line anymore. Please keep this in mind while reading the post which was written earlier.
Please also look at the online visa option for Thailand, it helps you to go to a separate counter and beat the queue.
I have been thinking about writing of Thailand visa on arrival for Indian citizens. My first visa on arrival experience has been with Thailand at the Suvarnbhumi International Airport in Bangkok. I am not counting the Nepal experience in this list because if you travel by air to Nepal you just have to show your passport and you can walk off. There is no visa required for Indians to get into Nepal. As Bangkok was going to be my first visa on arrival I was a bit apprehensive. I looked seriously at the list of required documents for tourist visa on arrival. I had all the documents with me as well.
In September, my flight was with Thai Airways. It was a short and pleasant flight. I watched two movies (it was about 4 hour Delhi-Bangkok flight) and the time went by quite easily. Only not sleeping at all leaves me very tired and a bit confused on arrival.
I generally don’t get lost on airports but once I did manage to go to the domestic departures instead of exit at Kuala Lumpur, Malaysia. I made no such blunders at Bangkok though. Soon I was standing at the visa on arrival queue at Suvarnabhumi. I filled the form, took out my picture and was wondering what all documents they would ask for. There are two queues for the visa, one normal and the other fast track. The normal queue costs 1000 Baht and the fast track 1200 Baht. They accept only Bahts at the visa counter and no other currency. You can change money before joining the queue. After a few international trips, I now prefer to carry dollar or pounds as they easily exchange at any airport. I took the express queue.
When my turn came, they just asked for the form, the photo and the money. Once the formalities were done, I showed the visa at the exit counter and there I was at the luggage belt! Duringthis trip to Thailand I exited to Cambodia. It was another visa on arrival but as I was traveling with Tourism Authority of Thailand they took care of my Cambodian visa. When I entered Bangkok again (as my flight to India was from Bangkok) I had to do another visa as I had a single entry visa. The second time as well, the process was exactly the same.
However, I am no way recommending that you don’t carry the requisite documents. There is no way to predict who will be asked what! I had all the relevant documents just in case they asked for it. But my first experience (and second too) of visa on arrival at Bangkok was a breeze.