e.type returns "mouseover" when "mouseenter" fires and "mouseout" when "mouseleave" fires. See an example:

$('ul li').live('mouseenter mouseleave', function (e) {

var target = e.target ? e.target : event.srcElement;

console.log(e.type);

...

});

it looks like "mouseenter" behaves like "mouseover" and "mouseleave" like "mouseout".