95B-OSR2 was my favorite for years.
I have not found a need for 64 bit computing at home yet.
The first place I can personally see needing software that can handle 64 bit data is right here. See the huge post id numbers?
signed int32 max value = 2,147,483,647
current message id = 1,123,013,431 (from the original Taldren forums bugged import - we only have about 750K posts, not 1.12B)
Well, I suppose we have a few years to go - actually we're probably fine and will never need to move to 64 bit software because of this. (half-way there - only about a billion posts to go!) It is a real pain, I have to re-write every version of SMF to handle such huge numbers. But this is the kind of reason to go to 64 bit. (even though there are ways to do it in 32 bit platforms)
I'm running a 64 bit machine with 32 bit software, like many today.
I forsee a time when bit-depth may not be a limitation like it can be now.
There's a 1 bit ADC algorithm somewhere I'd heard about in audio circles... not sure how it works. At a certain point bit-depth increases will become absurd.