Drunk Driving accidents are still accidents... This rules out murder 1 2 and 3... Involuntary manslaughter would be more likely to stick as it is more accurate to the situation. All 3 degrees of murder include intent to harm the victim... Again i say: Accidents are still accidents even if the person was drinking.
First degree murders as a result of drunk driving in my opinion should not be instituted. The reason is because it was not done in full conscious. It should however be a second degree murder or manslaughter. Every person should be treated fairly in a court of law and drunk driving is a serious felony, but not intentional murder.
The basis for charging someone with first degree murder is that First-degree murder is any murder that is willful and premeditated. Whether or not the person is intoxicated should have little bearing on whether or not the above is true. Either they planned and premeditated the murder or they did not.