I have the same setup as you.
I have installed:
-Brilliance 2, Dpaint AGA 4.5 and 5, for paint and animation Personal Paint 7 for paint, art and imagestudio for picture file conversion. I use Mainactor to convert anim5 animations to anim8 which scala plays back faster and smoother than anim5. Brilliance does this too I think.
-ScalaMM400, Adorage AGA, Clarissa for video and presentation.
-various utilities to create mpeg video form anim5.
-directory opus 4 is a must.
-Soundstudio is good for music, bars and pipes i hear is good as well.
Lightwave 3.5 and real 3d
With apps I think the golden rule is to run software that was made to run best on your hardware ie don't use paint programs like photogenics or arteffect that use layers and open 24bit windows, they were created at a time when the Amiga was trying to do things like a PC and Mac, and really need RTG and 68060 and still aren't as good as Pc and Mac equivalents. The AGA software is elegant, and fast because it uses the Amiga's strength: graphics and sound chips working independently of the CPU.
Games: gloom3d,Alien breed 3d, SlamTilt, Mansell's World championship racing, Sensible soccer, cannon fodder, deluxe galaga/pacman (not a lot yet)