The odd game - Settlers, A-Train, SimCity 2000 - think you get the idea of the genre (always hated populous, though).
Demonstrating things to kids at school (I'm an IT teacher, having once been a science teaacher) becuase the Amiga is brirlliant at showing some things a PC is naff at demonstrating - decent CLI, screenmodes where you can see RAM usage change, screenmode frequencies, the fact it boots really quickly, the fact it's older than all the kids!
Plus it's such a simple OS that it's easy to explain what's going on and then use as an analogy for the PC.
The old bit of DPaint.
And finally and most importantly, FinalWriter - surely the best word processor ever written. Soooooooooooooooooo much nicer than Word because it doesn't try to guess what you're trying to do and then be 'helpful'. The grammar checker works properly, the index works (unlike Word, which doesn't have one really) the contents generation system works in a user-friendly manner. Styles work ditto, the list goes on!