You may want to sell one day.
Easily recognisable, easier to sell.
E.g. Sovereigns, Perth Mint coins.
Don't pay too much of a premium unless it has numismatic value. It is best to know what you are doing when buying numismatics especially when paying a lot over spot.
Currently a gold sovereign is about $420
You can pay thousands for rare sovereigns.
Here is a list of coins...
http://www.wdavis.com.au/live-price-list.html
