Greenwood's 1827 map of London and surrounding areas (Excellent)
Snow's map of London 1859
Charles Booth's descriptive map of London Poverty 1889
A guide to alleys, courts, passages, and yards of central London
Historical Maps from the University of Texas Austin
Streetmap Contemporary Maps of London and the UK
Multimap Contemporary Maps of London and the UK
Mapquest Contemporary Maps of the world
antiquemaps Supplier of historical maps
MOTCO - Absolutely fabulous map website - no exaggeration!