Games that blows your mind

S.T,A.L.K.E.R Trilogy, F.E.A.R Trilogy, Wolfenstien Games. I think that 3 game series where hugely underrated as games. I loved spending time playing them, especially S.T.A.L.K.E.R Series. With that set of games you could also build your own custom packs, addons etc. So even if finished the game you could then build different cool custom styles etc.