Hi,
I personally think Brilliance 2.0 is the best bitmap paint & animation program on the Amiga. PPaint (Personal Paint) is nice and comes with Amiga Forever, but I really like the interface and keyboard shortcuts of Brilliance. Plus it has rarely if ever crashed on me. See if you can find a copy with the manual ... you won't regret it. It has everything DPaint does except the ARexx commands, but the interface is so well-thought out and convenient... very productive.
Also if you intend to work with 3D, you might want to look for a program called PixelPro, or Pixel 3D Professional. It's a handy little app that will take your 2D bitmap art and make 3D objects out of it.
Welcome to the wonderful world of Amiga art :-)
Hope that helps
t'byte