How much of a difference will I see with 128mb vs 64mb?
None, unless there are programs that require more than 64MB ram and I don't know any.
Basically as long as an Amiga has enough fast ram to load programs into it then adding even more ram won't speed anything up. An Amiga with 2MB fast ram is just as fast as one with 128MB or more.
8MB or more makes a nice WHDLoad setup. 64MB or more is nice for audio editing as it means you can load an entire song at cd quality into memory and manipulate/edit it. Same applies for graphics files. 128MB is even nicer as you can edit larger audio/graphics files and also preload whole CD32 games into memory with WHDLoad (such as Darkseed with speech). It's just the luxury factor, buy as much as you can afford is my advice. Plus, you never know...in the future you may need that ram for a new program that may get released, or for a new card that you may buy.
