Of all the plates below, my favorite by far is the "Lucille Ball Tribute Plate" done by artist, Mike Hagel in 1982. I was just 3 years old when this plate was produced and saw it for many years and finally acquired it. Very exciting! 

But of all the plates, perhaps the most valuable is the Danbury Mint Test Plate. There were 99 made and a much larger plate than others, and can sell between $300 and $900. This is actually the second Danbury Mint Plate that I have owned. Unfortunately the first one, I purchased for $129 (including shipping!). Unfortunately, the seller did not package this item appropriately and so when I opened up the box, it had been wrapped in newspaper and broken into hundreds of pieces. Needless to say, I was almost in tears. Several months later, I found the one pictured below and made SURE that it needed to be packaged with extra love and care. It is now displayed beautifully in the cabinets.