Well it would seem that TV Paint is voted the best (hey it actually is the best for standard amiga g cards).
Fot AGA I still like DPaint 5.5.
ImageFX for processing is a good choice.
If you are lucky enough to have owned or do own an Opal Vision card, OpalPaint v2.? is by far the best Paint/Processing graphics tool ever on the Amiga. I sure wish Asha had got the deveopers to release it to be ported to CGX or Picasso it would have been killer.
I do agree that TV Paint is the best out there major shortfall is only three layers but is the only thing I find I could use more of.