FRANK LLOYD WRIGHT's Buildings - 1867-1959
JORN UTZON and the Sydney Opera House - 1918-
JOHN NASH's Buildings in Brighton, England.
FLATIRON BUILDING
LE CORBUSIER - 1887-1965
GUSTAV EIFFEL
MIES VAN DER ROHE - 1886-1969
ANTONIO GAUDI - 1852-1926
OSCAR NIEMEYER
Pier Nervi - 1891-1979
Alvar Aalto - 1898-1976
Louis Kahn - 1901-1974
Frank O. Gehry - 1926 -
Kenzo Tange - 1913-
Frei Otto - 1925
Sir Christopher Wren 1632-1723
Nichlas Hawksmoor 1661-1736
Sir John Vanbrugh 1664-1726
Robert Adam 1728-1792
RENNIE MACKINTOSH - 1868-1928
 FAMOUS ARCHITECTS
STYLES & PERIODS IN ARCHITECTURE
NOTABLE BUILDINGS IN EACH ERA
AUSTRALIAN ARCHITECTURE

Some more links:
Architecture page from Princeton University
SPIRO - over 13,000 images
Renaissance and Baroque Architecture - Renaissance and Baroque Architecture:
Palladios - Italian Villas. The Renaissance architect Andrea Palladio shaped the world that surrounds us today. Some of his most influential villas survive in the Veneto region around Venice, Italy
A site about renaissance architecture: http://www.usa-people-search.com/content-renaissance-architecture.aspx    (recommended by Helen - thank you)

RECOMMENDED BOOKS
Le Corbusier: Architect of the Twentieth Century
Kenneth Frampton & Roberto Schezen
Frank Lloyd Wright: America's Master Architect
(1998), Kathryn Smith
Frank Lloyd Wright's Taliesin & Taliesin West
(1997), Kathryn Smith
Frank Lloyd Wright's Interiors
Thomas A Heinz
A Frank Lloyd Wright Companion
William Allin Storrer
The Life & Works of Frank Lloyd Wright
Thomas A Heinz
Frank Lloyd Wright
Trewin Copplestone