Yeah Mackaydon, Spent many years and much treasure developing a WW collection of 1840 - 1930 in a beautifully preserved 1930 Scott's Junior stitched hardback stamp album. Lots of fun, but ready to move on to something else. I collect only postally used in US, and find 720 & 721 extremely interesting. They were the first class standard definitive issue from 1932 - 1938, 6 years during the height of the Great Depression, and for instance I have found 12 distinct shades of the 721, 13 recut plate varieties, along with hundreds of interesting cancels. It was hard times and ink mixing was variable over it's printing life, along with the recut plates to keep them alive for more printings, all of which make for stamp collecting at it's finest. You, a stamp, magnifying glass and totally uncharted waters, as you search for varieties everyone has ignored for decades. You can literally buy them by the pound already soaked off paper for just a few bucks. I paid $10 for my last pound of these, which runs at around 7,000 stamps, and I'm having a blast collecting them. I also collect other issues the same way, like C23, C46 with actual Hawaii postmarks, j79-j86 which are the Postage Due issue from 1931 - 1958, America's longest running issue with tons of shades, colors, and plates being recut for 27 years! Talk about a complex issue, these really bog me down, but are fun collecting and not expensive either. Then I pick up SOTN's at shows and from other collectors and have managed to acquire hundreds of them, trading for the majority of them. I am just getting settled in from a move and will try and get some scans up of some of what I collect next week to give you guys a better idea of the fun you might be missing out on.