My usual fare for the PC consists of RPGs, mixed up with some RTS. Recently, however, I'm inclined to try some shooters. The ones I've played and liked are, more or less in order: Mass Effect (an action RPG, yes, but it plays mostly as a shooter.), Rainbow Six Vegas 2, Halo 1.
I'd like to try something Present-Day or Futuristic for a setting. I absolutely don't play multiplayer, ever. I don't mind games that aren't very recent. The ones I consider are CoD: Modern Warfare, Battlefield: 2142 and S.T.A.L.K.E.R.
What's your opinion on those? Any other FPSs to recommend? Thanks in advance!