I like the idea of having all of the presidents on 1$ bills or something. It'd be like the 50 different state quarters, except there would be around 30 dollar bills. All dead presidents excluding those on other bills or coins would be available.
And for God's sake, what the hell is Grant doing on the 50? Remove him immediately and replace him with Truman or Reagan.
Back before 1928, paper money designs changed quite frequently. Then they switched to the current size of paper money from a previous size. As a result, we quickly ended up with a uniformity of design that US paper money had never had before. Grant just happened to be the president that was on the $50 at the time. Personally I favor replacing Grant with Henry Clay and if we ever get a circulating $200 or $500 bill again putting Chief Justice Marshall on the front and the Supreme Court Chamber on the back. This is because with the current exception of the $50 there is a relationship between front and back of the note. So for all you fans of putting Reagan on a piece of currency, what would you put on the back?