It's still murder, though, under US law, it's 3rd degree murder.
In addition, average jailtime for manslaughter in 2003-2004 was 5.9 years. Average jailtime for murder was 18.2 years, with a non-parole period of 14.4 years. Last time I checked, it's not hard to live for 18 years after you've killed someone.
Source:
http://www.theage.com.au/news/nation...377206386.html