Genoom is a rather new online genealogy service (see my earlier article at http://blog.eogn.com/eastmans_online_genealogy/2008/11/genealogy-meets.html) that features some excellent charts. To show the sorts of results that are available, the company has made public a chart of the Royal Family of Spain (11 generations).
You can see the chart at http://public.genoom.com/trees/familia-real/felipe. Make sure you "click-and-drag" the chart to see how it moves around.
An brief explanation of the chart is available at: http://blog.genoom.com/2009/03/12/family-tree-of-royal-family-of-spain/.