I noticed today after much fiddling that .hide() causes the parent element to loose its height().
In other words, height() won't work on elements that have display:none -- causing me to use .hide() only AFTER I've done my .height() - based calculations. I suppose that makes sense but I somehow never really thought that element.height is an attribute that gets set to 0 if display:is set to none...or whatever is actually going on.