God I loved so many.
I think the main one for me, which really got me onto really wanting an Amiga was Dungeon Master. I loved the two-player Bloodwych as well which myself and a friend used to play all the time - getting pretty bloody close to finishing it as well.
Others that spring to mind are:
Captive 2: Liberation :P (just good fun)
Eye of the Beholder Series (great games to play after Dungeon Master)
Legends of Valour (one of the first games I had - thanks mum!)
Galdregons Domain (saw this originally on an ST and it looked fun!)
Captive (too bloody big and dont think it can be finished)
Elvira 2 (no where near completed this game - should do really)
Waxworks (goryness fun!)