I hear Metro 2033 is pretty good, if your computer can survive it. STALKER requires patching and some people loathe it (seems to be rather polarising), but again, it's apparently good. Honestly, I'm afraid I'm just not much of an expert on FPS games. That said, allow me to suggest the Marathon trilogy [http://source.bungie.org/index.php?title=Get_Marathon]. It's not modern by ANY stretch of imagination. That said, it's good, the single player campaign (all it has, really, with multi as a poor afterthought) is pretty amazing, and it's free. Might want to try it.
Was going to recommend Bioshock, but apparently you already plan on getting that.
Oh, and F.E.A.R. is apparently set in modern times, only with psychics and robots. Or something. Never played it myself and don't intend to, but again, it's supposed to be a strong single player campaign, and from the health bar school of FPS games.