I've recently discovered TechNoir, and I'm fairly impressed. It's nice and simple as far as the system rules are concerned, but as it's a cyberpunk/noir setting, the complexity comes in the form of the plot and investigation. For those more interested in the roleplaying aspect of roleplaying games, I strongly recommend checking it out. One could call it "Shadowrun, without all the dice and magic." Although, it wouldn't be too difficult to adapt the system to the Shadowrun setting.