I was 12 when I got my A500, so Hollywood Poker Pro was probably my favourite for quite a while.
Others that I really liked;
Bad Dudes
Space Harrier (amazing with a mouse)
Arkanoid
SotB II
Bubble Ghost
Aaargh!
Way of the Little Dragon
King of Chicago
Hybris
Faerie Tale Adventure
Starray
...I could just keep going.
