Question

So I am looking for a way to remove all list items with one click, not that hard, but to give it some nice effect I wanted to let the first slideup and remove this, once the first is remove do the same for the second list item and so on, until every list item is removed.

Answer 1

Following removes all items in list sequentially at one time:

$('button').click(function() {
    var $first = $('#list li:first')
    removeItem($first);
})


function removeItem($el) {
    $el.slideUp(function() {

        var $next = $el.next()
        if ($next.length) {
            removeItem($next)
        }
        $(this).remove()
    })
}

DEMO: http://jsfiddle.net/UzPy5/2/

To remove individually can use