As far as first person shooters go, Far Cry was the least repetitive I've ever played, as well as the most non-linear.
That's the one thing I didn't like HL2. It was very linear. You always go through the game in the same way, go through the levels in the same way, and go through the same procedues. That's why those games have such little replay value. I think of those games as an interactive movie. Extremely fun and engaging the first time you beat it, but pretty much worthless once you do. Not really worth buying unless you're gonna do a lot of multiplayer.
Far Cry was really pretty awesome as a single player, compared to the others I've played, and as I mentioned, the most non-linear and open-ended.
But what really sold it for me, was that its multiplayer. Simply, the best multiplayer FPS game I've ever played. It was very smooth, fast paced and it had good hit detection. The other thing I liked was that the game would reward people who had good accuracy a lot more than other games I've played. You can kill a person extremely quickly if you're good; otherwise you're hopeless. Of course head shots are best. This is extremely discouraging for noobs. I also liked the binoculars and the sniper rifle. Even though the levels were large, you could make kills from extreme distances.
I would piss a lot of people off, because they didn't understand how important sound was, because the game's sound goes from pretty loud to very quiet, so I'd use good headphones and snipe people off in the distance for a while. Someone would get pissed and try to sneak up behind me, trying to catch me while my guy was prone on the ground with his sniper rifle--but I'd hear his footsteps before I was even in his line of sight--so I knew he was there before he could see me. So when he got near, I'd sprint off and shoot him in the sides--flank him, in other words.
Then I'd continue sniping.
Idle_mind--Yeah, I did the clan thing too for a while. I was in 760. Don't know if you've heard of them. Got boring though.