International purchasing and selling website you cannot ignore, see Coins' rubric. If you're patient, you can entirely complete your collection. However, sellers are only selling to make as much money as possible.
Great website of numismatology, Compagnie Générale de Bourse is fortunately more than a huge catalogue of coins out of reach, it is also a website giving a long list of interesting links. You will see the French ideal collection.
A website where you can see great ( English, mainly ) coins of all times. If you want to see an ancient coin in its original state or amazingly preserved, that's where you must go.
A personal Website
of a nice world coins' collector (coins and
banknotes), see the list of the missing coins and the doubles.
Guillaume Brisse's collection
A personal Website of an other nice french world coin's collector, Guillaume Brisse, who live in the Pacific.
Tony Clayton website
An excellent personal website about British coins. If you master English well, you will learn a lot on webpages by Tony Clayton, I invite you to visit them while clicking link former.
Olivier Robin's collection
Olivier Robin shows on Internet, since 1999, a very interesting world coins collection. He owns British coins I really wanted to have before I myself found and purchased them. He also writes and you can read most of his texts freely. So for those who enjoy reading and learning, go and visit his website !
Coinwiki.co.uk is an interesting English numismatical website dedicated to giving information about British coins and relevant history from 1816 to present day.