It is criminal that I haven't seen the original Outlast nor Siren mentioned. That said, the original Silent Hill remains my favorite horror game of all time, but in a Top 5...
6-10: Silent Hills 3, 4, 2, Resident Evil 0, and Resident Evil 2 REMAKE
I just heard big praise for both Outlast and Condemned yesterday on Spawnwave. I definitely need to try those.
Retro Tech Select - My Youtube channel. Covers throwback consumer electronics with a focus on "vid'ya games."