I'm not sure what this is asking, or if this is the best use of a coin section of the forum. How about we have a thread just for numismatics (yeah I'm a currency nerd) Frankly, if you have a rare coin and want to have it appraised, chances are its been sold on ebay before, just do a search for completed auctions. Of course there is some debate about the price discovery function of ebay, but that will tell you if you have a million dollar coin or just a regular generic round someone made to imitate one.
How about a coin pr0n thread? Pictures of coins we have, pictures of coins we want, it could aslo be called "you want, you lose" Here is my contribution of the 2006 reverse proof eagle, one of my favs.