Right now all my silver "stacking" is with 90%. Just ordered my first three silver dollars.
For whatever reason having a bunch of circulated 90% coins, just does it for me way better than ASEs (although I do enjoy looking at my son's 2004 ASE proof, what a beauty!)
Any of the rest of you totally caught up in stacking historical coins over their modern bullion counterparts? I think I'm gonna start targetting historical gold coins -- own two sovereigns already and looking to start adding some pre-32 eagles and the like. . .