DOOM 3 was good. You could try some of the war games, like the Medal of Honor series, or the new Call of Duty. I played Medal of Honor: Pacific Assault, and had a good time with it.
If you want a really intersting first person game, try Thief, the first one for PC if you can get it. It should be super cheap. It isn't a "shooter", but I think it is far better, and honestly one of the best games ever.