If you see a differnce in how CSS line-height is handled in an Ittrium site versus some other sample site, check the doctype. In strict mode, for inline elements like an anchor tag, the minimal line height that applies comes from the containing block. So while an explicit line-height on the anchor can make the anchor text taller, it can not make it any shorter than the line height applied to the containg block.
This was noticed in a picture caption where the bounding outer box was rather narrow, forcing the caption itself to wrap. When trying to get the multiple lines in the caption to squeeze together, setting the line-height on the anchor had no effect on the minimum. The line height had to be changed in the caption div that wraps the anchor.