I did originally think I'd overdone it when I put 256MB in my A1200, but one use I have for that is having my OS in RAD. I have several OS "snapshots" that I can choose from on cold boot, then all subsequent warm resets run from a 32MB RAD. It's quite nippy.
Not many amiga applications can make heavy use, though photogenics is one. Ports of old PC games can be quite memory hungry though.
Will be interesting to see what people do with these new ZorRAM jobs in their big box machines.