Silent Hill
Silent Hill 2
Silent Hill 3
Silent Hill 4: The Room- crazy hikikomori trapped in his house
Silent Hill Origins- It's about a trucker who gets lost in SH
Silent Hill Homecoming
Silent Hill Shattered Memories- to different to say a remake of the first
Silent Hill Downpour- not released yet

I don't play survial horror games but I do like to study the games... with the exception of 4 all other games were rated high... I'd say get them