This is a much better solution for non-trivial cases than any in the absolute centering article. The only competitor is the table-cell technique with vertical align center; but that requires more markup, and there is some tricky interaction with the outer display:table since table-displayed element follow different sizing rules (basically, you can't position:absolute them with 0 top/left/right/bottom offsets since their intrinsic size overrides such declarations).
In short: the ghost element technique works best :-).