I recently received an email from a reader asking me what I think affects coin values most. This is a tough thing to put a definitive answer on because there are many contributing factors we need to consider when working to determine what affects a coins value. I am going to leave comments open on this post so you can also suggest what affects a coins value most.
Now, at the time of this writing (July 2012), we are four plus years into the recession. We have seen gold coin values sky rocket as a result of investors flocking to gold and precious metals as a safe haven from equities and other investing instruments. This has affected quite positively any coins value made of these precious metals regardless of the minting country, relative artistic value of the coin, or the coins condition. Quite simply it's worth its weight in the least in the metal the coin was minted in.
In hard times precious metals fair the best. Coin values have historically increased when concern for national economic strength is highest. This is true because there is only so much of the metal available that goes into a coin thus increasing the coins value. Since 1999 gold has risen per troy ounce from $250 to over $1,700. The math here is simple as it relates to gold coin values; they have increased in tandem with the price of the metal.
Now let's take a look at silver coins value over the same time period as gold. Since 1999 silver has risen per troy ounce from $5 to over $48. As we have seen in gold coin values the same is true of silver coin values.
Lastly, what about the value of the coins rarity, artistic value, and do these as well as any factors contribute to a coins value? When I think of specific coins of mint oddity, or limited run, "yes" of course there is value to be considered here however when considering volume and coin value over all it is pretty clear, to me anyway, that the coins value is most affected by its content particularly a coins value in gold or silver.
In closing, and to answer the question from my perspective, what affects coin values most is their precious metal content. No oddities or limited run coins have matched the velocity and value changes that gold and silver coin values have.