I already have both L4D, and amnesia. Metro will go on sale during the holidays for you, im sure.
Nothing really caught my eye this sale,ive played or own everything on sale cept fear3.... but im not spending 30 bux on it thats for sure, lol. and good luck on amnesia, make sure you are alone and its dark. I had swamp ass the entire length of that game its unbelievable how scary it is