Yeah, don't dump ole Hickory. I'd say displace either Grant or Cleveland. In addition, dump FDR and put Ronnie there too - there's nothing that says you can't have him both on a bill and coin!
I'm actually surprised by the Old Hickory fan club here. I guess a lot of conservative history buffs out there. Anyway, Grant's riper for the pickin' anyway. When it comes to that era, LINCOLN is the man, not Grant.