I don't have Last Light (yet), but Metro is definitely the best modern single player FPS out there. Not an amazing value though as I can't really find good reasons to replay it.
I also really like Far Cry 3, but I wouldn't call it an RPG. It's an open world FPS with excellent gunplay, essentially. If you like the gameplay, there's plenty of content to go through, much more than in Metro for example.
I personally would recommend Mafia 2, Dishonored, Antichamber, Binding of Isaac, FTL and all the Braid, FEZ, SMB, Limbo and other indie platformer things for a start.