They drive on the left side of the road here!
Walking is fun the first night, maybe. But you're on vacation.
The island's road system is well developed so you can get everywhere with a scooter. There are many scooter accidents in Samui, mainly because the drivers are tourists who lack motorbike experience (no one will check you even have a driver's license), are not used to driving on the left side of the road, don't feel like putting on a helmet, and provably all of the above. So please, if you get a scooter, be careful.
Expect to pay 150-200 a day (your rate will be lower if you rent for a whole week).
If your hotel rents out scooters, prefer renting from it. Other rental shops will want to hold on to your passport; don't ever do that. Your hotel doesn't need that from you.
If you sleep in Chaweng beach you'll be a walking distance from the many restaurants and nightclubs on the long Chaweng main street. That way you can party and not drive home drunk.
All taxis on Samui island go for a fixed price (300 baht is the standard rate inside Chaweng).
From the airport, there's a private taxi service which is quite expensive (you can find a partner and split the fare) or there's a minibus service that goes along the island's beaches and drops you off at your hotel for a reduced fee. The drive is short and there really isn't much reason in taking a private taxi unless you are in a rush or have too much money for your own good. If the case is the latter, I don't mind taking some of that dangerous money off your hands.
