Question: coins are the most valuable?
Answer: 1804 Silver dollar, Class I ($4.1 million) ... 
2007 C$1m coin ($4.1 million) ... 
1343 Edward III florin ($6.8 million) ... 
1787 Brasher Doubloon ($7.4 million) ... 
1907 Saint-Gaudens double eagle ($7.6 million) ... 
1933 Double eagle ($7.6 million) ... 
1794/5 Flowing hair silver/copper dollar ($10 million)