When you're setting up properties for a "Lookup" field type, setting a default is not an option. I believe SharePoint does this because it can't guarantee a user won't delete that value from the lookup list (thus breaking the default lookup relationship). So, as far as I know, the only way to set a default on a lookup item is similar to the method above. If it's the first item in the list, that method works as is. If it's something in the middle of the list, you'll have to employ a more creative jQuery selector to get to the option you want. for instance, if the option you want has a value attribute of 3, your line would be...
$("select[title='Status']").children("[value=3]").attr("selected", "selected");});
This will only work under two conditions: Your lookup list isn't modified in such a way as to change the value of your target and the lookup list is <= 20 items. Once you exceed 20 items on your lookup list, SharePoint changes the game and renders the control on the form as in input element with a small button next to it to render a dropdown list. The process for selecting an item in that type of list is quite different. Of course, with the SPServices tools, you have the option to override that as well using the '$().SPServices.SPComplexToSimpleDropdown' function.
You could try to use a ':contains' selector to get to the option you want. That would be independent of the value attribute but contains can give you multiple results. For instance, if you lookup list includes the items "Open" and "Open Tomorrow", something like the following would return both items:
$("select[title='Status']").children("option:contains('Open')").attr("selected", "selected");