How can I get form data with JavaScript/jQuery?

Is there a simple, one-line way to get the data of a form as it would be if it was to be submitted in the classic HTML-only way?

For example:

<form>
    <input type="radio" name="foo" value="1" checked="checked" />
    <input type="radio" name="foo" value="0" />
    <input name="bar" value="xxx" />
    <select name="this">
        <option value="hi" selected="selected">Hi</option>
        <option value="ho">Ho</option>
</form>

Output:

{
    "foo": "1",
    "bar": "xxx",
    "this": "hi"
}

Something like this is too simple, since it does not (correctly) include textareas, selects, radio buttons and checkboxes:

$("#form input").each(function () {
    data[theFieldName] = theFieldValue;
});