#1: The Moon Shack
The Moon Shack is (as you can probably tell) a pretty informal place. There's no dress code, although you'll often see people in swim trunks because it's located by the ocean in a popular tourist resort named Kompong Som. The handmade sign is a nice touch and the people in the bar seem friendly. The Moon Shack is cozy enough that for about US $10 you can often buy the whole bar a round!
Next: The Cadillac Bar