If you are flying into Cambodia and Laos, you can fill out a form, pay your money and get a visa on

1st trip to Bangkok. Could someone please help me with info. as to best transportation from airport to hotels in "downtown". If I have to take taxi then how much baht should it be. I will be staying at Le Meridien Bangkok only for first two nights to get my feet on the ground.
Taxi is easiest. Just follow the signs to the taxi line. Tell them to use the meter (they should anyway) and it should be about 350 baht. You will have to pay tolls for the expressway, travel from miami to hyderabad 70 baht. Unless you are arriving at 2 am, you want them to use the expressway travel from miami to hyderabad (they will ask).
I always go to the taxi line. When returning to the airport, after a couple of weeks of shopping in BKK and other parts of Thailand, I need a mini-van to take me to the airport! My hotel arranges this one for me, and it is a flat rate of 600 baht, but at least I know that my 3 big suitcases will all fit. Taxis are small cars. The trunk is very small. The taxis are not run on gasoline. They have a propane (?) tank in the trunk that takes up about half the space! But I always have a bag riding in the front seat on the way into Bangkok.
If you are flying into Cambodia and Laos, you can fill out a form, pay your money and get a visa on arrival in both countries. If you are arriving overland, you'd have to check to see whether visas are issued at your proposed point of entry. In both cases you'll need 1 or 2 passport-sized photos.