QUOTE(ricster @ Oct 10 2006, 12:05) [snapback]1222624[/snapback]
Check the poll, it reads "What FPS game do you play? Either in single player mode or online."
HTH

I actually played some DeusEx2 the other night because of this thread. While still a good game I get bored of the 'go to A, do B, come back to A and I'll give you the code to C' stuff a little too easily.
But almost all the games listed are famous not for their singleplayer but their multiplayer.
Also, playing offline doesn't necessitate single-player. I used to play Doom, Blood, Quake etc. over LANs and serial connections. There was nothing like coming home at lunchtime with a mate for a few rounds of DM4 on Quake on two PCs

On DX:
Deus Ex 2 isn't as good, not nearly as good.
Deus Ex is linear in its plot and its basic objectives but what really sets it apart is the number of ways you can choose to accomplish it. It's technically possible to complete the entire game without killing a single entity, although it's very very difficult, so much so that I've never even tried it. You can specialise in big, exploding things, little exploding things, computers, lockpicking, stealth, long-range weapons, brute strength, whatever.
Even something as small as, say, getting over a shorted eletrical generator. You could use your electronics ability to shut down the circuits, you could try sprinting through it and sacrifice some health, or you could lift crates to make a small platform off which you can jump over the electricity safely. Think of that, then multiply it throughout the entire game. You can shape almost every level, every encounter to your playstyle.
Deus Ex 2 offers the same but it doesn't pull it off as impressively. I never even finished DX2, come to think of it, I'll need to try it out again

The plot, while a bit build-your-own-conspiracy-theory, is immensely entertaining, more so than any Dan Brown book

, and as Gaz says, can awaken your interest in some topics, which you can then research properly. That's not to say that everything in it is pulp junk: you can read newspapers and excerpts from books in-game and there is much illuminating about them.