Interesting list of the Ten Greatests Maps from The Daily Mail, via Flowing Data.  Interestingly, Google Earth made the list.  "Is Google Good for Geography?"  I think I would have liked to see the Hereford mappa Mundi on the list.  A commenter on Flowing Data suggested Snow's Cholera map.  I suspect the intention of the list is to bring attention to maps that aren't necessarily the ones you would think of.  The article is authored by Peter Barber, head of Map Collections at the British Library.  He is also featured prominently in the BBC 4 production The Beauty of Maps.  If you can find a copy of the documentary it is worth checking out, otherwise the website has some nice interactive features and clips.