Actually Proof 70 silver eagles are quite common and they are today's fad. When they first started slabbing and grading Morgan dollars people paid outrages prices for MS-64 coins. A few years later and the bubble burst. The $200 coin was now worth $80. That will also happen to the Proof 70 and 69 coins as well. The silver eagles are only collected by the younger collector not us old timers. The 1916-D dimes that I bought in the 1960's for $20 are now worth $800 or so and are going up faster than the silver eagles. They are however really rare with a mintage of 264,000. The rarest proof eagle in the 1995-W at 30,125 so that would have been a good investment then but now it is over $6,000. The 1994-P proof eagle has a mintage of 372,168 but it's value is not as high as the dime and it would be a lot easier to sell the dime. I am afraid the modern fads caused by the dealers and PCGS or NGS will first of all hurt numismatics but soon separate a man from his money. I would look into real rare coins. The silver state quarters only have 2 years that actually have a high value and it is best they are kept with the rest of the proof set if bought that way. They are a good investment now but what happens when they start the national parks quarter program will they then be forgotten by he masses. To me rare coins are the ones minted before WW II that have low mintages. Finding these coins in grades very fine and above are not easy and they make the better investment.