devon, LClock was a good try, but I didn't liked it.
It's nice to a have an auto-hide feature, but when planing (what else could I be using a calender for) it bugs me. I know its an option and when disabled the calender stays visible unless you click it away. But here is the thing: in a Windows environment you're always looking for the [x] to close the window or for a button. None is there. I found it hard for me to adapt to be clicking once again on the clock to hide. A smarter solution IMHO here would be a [pin] button, which when clicked prevents the auto-hide and vice versa. This solution enables a situation-based auto-hide mechanism and not a general decision.
But that's not what I disliked in the calender: it doesn't show the week number, nor does the default XP calender, nor the Vista one (as far as I remember).
Anyway LClock is still the best one I've tried, but the search continues ...