I love Day-O; it gives me exactly what I want in my menu bar, and in the least space of all the possibilities I've tried (and its lack of Calendar integration doesn't bother me, because I don't use Calendar).
One star off, though, because I can't move its icon from the left of the text to the right, where I'd much prefer it.
(Day-O's time-keeping is weird: it's mostly always a sec behind Apple time.)