I've given it a lot of thought over the years and I think I figured out how I want U.S. Currency changed, i.e. I'm bored with a lot of the faces on money now. This is how I would change them.
1 Dollar Bill (Washington)-Since he was the first President I guess he can stay on the dollar bill, although a strong case can be made for Lincoln as being the best president.
2 Dollar Bill (Jefferson)-He can stay, but I don't know if he'd want to. The 2 dollar bill has so screwed so many people out of money throughout the years. Case in point. When I was ten I was given a two dollar bill and was told to keep it as like a collectors item. So I tucked it away in a coffee can in my room which eventually ended up in the attic with a bunch of other keepsakes (little league trophys and what not). When I was 28 I was snooping around my parent's attic and found it. I took it to McDonalds along with another $1.17 and bought a cheeseburger value meal. From my estimate, 18 years earlier I could have bought a heck of a lot more at McDonalds or anywhere else with that two dollar bill. A currency collector today would give you exactly two dollars for a two dollar bill.
Five Dollar Bill (Lincoln)-Except for the aforementioned switcheroonie with Washington, I did the five as it is.
Ten Dollar Bill (Hamilton)-I know Hamilton was a great guy and all, but I don't care much for him on the ten. I'm a big fan of having only Presidents on the currency (I don't why, I just am). I'd replace Hamilton with Kennedy. Since Kennedy was a democrat, to be fair I'd also like to see Theodore Roosevelt on the ten. I flip flop back and forth between the two. Did you know William McKinley was briefly on the Ten Dollar bill? From I think 1902 to 1929, not sure why they took him off. I'm fairly certain he was put on because he was assassinated (they did that with Kennedy and the half dollar).
20 Dollar Bill (Jackson)-I think Andy Jackson probably deserves to stay on the 20. President Garfield was on the 20 before Jackson (also because of assassination).
50 Dollar Bill (Grant)-A really great general but not a very good president. I'd replace him with Theodore Roosevelt (if he's not on the ten dollar bill) or John Adams (the first one). Little John Adams deserves a lot more respect than he gets.
100 Dollar Bill(Franklin)-Like I said before, I only want to see Presidents on currency, otherwise this would have been a good choice. My vote goes for Harry Truman on the 100 dollar bill.
Just for trivia's sake, the following bills are no longer in circulation;
500 Dollar Bill (McKinley) 1000 Dollar Bill (Grover Cleveland) 5,000 Dollar Bill (James Madison) 100,000 Dollar Bill (Woodrow Wilson)-This bill was printed but was never put in to public circulation.