Classic Amiga please. But do good games come from wanting to please others, or by pleasing your self? (I know..). But most interesting games for me the last few months have been of the rather original Heavy Rain and Braid type.
Having said that. Turboraketti / Xpilot type game online for Xbox live arcade is probably what I would love the most. Massive online potential.
But for Amiga, a really good action-adventure game in the Prince of Persia, Flashback, Another World vein would truly rock.