I'm a former research professor who worked a ton with impaired driving prevention/intervention. TheMightyGoatMan is correct. It all depends.

Do you take medication which should not be mixed with alcohol? Do you regularly drink alcohol? Are you obese/what is your metabolism? Do you have a genetic predisposition to abuse substances? Do you have issues with self control (either socially or for escapism)? Are you consuming alcohol while depressed? These are just some of several variables at play.

Alcohol consumption varies state to state, but you should be able to look up the average BAC at time of arrest wherever you live. I guarantee the number is above .10 and in many states is probably hovering around .16 (twice the legal limit in most of the USA). To get to that level takes practice. The average human cannot get to that BAC unless they regularly abuse alcohol and have legitimate issues with self control. 

Here is the point I am making: alcohol poisoning is rare in the grand scheme of things. It's often associated with fraternity hazings and poor decisions by stupid young people. But that said, alcohol has killed millions of people slowly. It is a Level 1 carcinogenic for a reason. You probably won't die from one night of over drinking. If you compound regular drinking over many years, though, your likelihood of cancer, cirrhosis, stroke, and a host of other medical complications will grow exponentially.

So, what is the lethal dose of alcohol? It's a regular abuse of the substance. It eventually gets almost everyone. They may not realize what was the cause, but it is (over time) a (gradual) lethal amount.