The Inland Taipan snake is considered the most venomous in the world.  They are located in South Australia.  Although they have the most toxic venom of any animal on Earth they are not the most dangerous snake. 

 The Inland Taipan's venom can kill an adult human in 45 minutes.  One bite can kill up to 100 men. Australia only have 2-3 average snakebite deaths per year. 

The world's deadliest snake is the Hook-nosed Sea Snake (Enhydrina schistosa), which has an LD50 (lethal dose for 50%) for mice of 0.02 mg/kg and venom yield per bite of 7-79 mg. 

Hook-nosed Sea Snake

In terms of the snake that yields the highest amount of venom per bite, that honor goes to the Eastern Diamondback Rattlesnake (Crotalus adamanteus) at 200-850 mg. 

Eastern Diamondback Rattlesnake

A few other snakes with yields ranges that overlap the Eastern Diamondback include:

Common Taipan (Oxyuranus scutellatus):  120-400 mg

Gaboon Viper (Bitis gabonica):  350-600 mg

Spectacled Cobra (Naja naja):  150-600 mg

King Cobra (Ophiophagus hannah):  350-500 mg

Western Diamondback Rattlesnake (Crotalus atrox):  175-600 mg

Red Diamond Rattlesnake (Crotalus ruber):  120-450 mg

Bushmaster (Lachesis muta):  200-500 mg

the large king cobra

Juvenile venomous snakes are often the most dangerous because they cannot regulate the amount of venom they inject and have the potential to inject even larger amounts of venom than mature snakes.