Originally Posted by Gorath 
Metro 2033 on Steam for only 2.50 EUR.
That's a very atmospheric, emotional, story driven FPS. Superb production values, some greatness but also a couple of annoying things. Highly recommeded if you like your single players FPSes definitely not average.
Steam also has it on sale here in NA, but for $5.00
+1 to your description. I think Metro 2033 is an underrated game that a lot of people missed. The only negative that I can think of was how high the system requirements were.