If you want War games then get Battlefield 2 and go with Project Reality Mod.

BF2142 if you like mechs, but not nearly as good.
Quake Wars if you can pick it up cheap enough the community is still there but not as active as say BF2
Counter Strike Source- Although you should already have it
If for some reason you dont like CSS then go with CS1.6 still loads of people play it.
Rainbow 6 vegas/2
Free online games:
Fear Multiplayer- good fun
Americas Army2- hard and i find it a lil dull but some people like it
WarRock- I cant stand this but I have a few friends that loved/love it.

Others:

Orange Box is a bargain!
Brothers in Arms can be fun
Crysis
UT3- wait for a steam sale though you will get it dirt cheap
COD4
Ghost Recon
Operation Flashpoint

I hate these posts.
"Hey I have just spent the last 6 months researching parts and finally bought them. Do you think that they are any good?"
...like you dont know what they are.

p.s.
Just to make you feel better unless you have an i7 and 3 way sli gtx295 your PC sucks :P

CrossFire is for Ati, SLi is for nVidia Cards.

Both cards have to be exactly the same. Model/Make Everything.

So you couldn't sli a XFX 8800 512mb gtx with a BFG 8800 320mb gts oc for example.

?? Has no one played Killing Floor the UT2k4 mod?

It is a game made from that. Uses the Unreal 2.5 engine so you can expect to see more of the same.

take two do own the rights: http://www.take2games.com/index.php?p=games&title=dnf

Crysis: £10 - anywhere! That if you dont already own it. Warhead sucks and Crysis Wars is dead. No I wont be buying thiis.

That and Crytek defected to Consoles; f**k'em!

You will get drops in fps for a whole load of reasons. Internet Lag. Many Players/Effects/Objects on screen etc. If you run a gtx260 you will still have drops depending on the situation it just wouldn't be noticable.

I think your CPU is fine for any Source game. Its a dual core so shouldn't be a prob howver you will run into bottlenecking problems with games like Crysis, maybe picking up a Phenom X3/4 black would be a good idea, your mobo should be compatible.

If you go with a gtx260 it will max everything fine unless you plan to run at HD res. As in 1900*1200 or whatever it is the 260 really suffers from large fps drops you will have to go with a 4870X2 or gtx275/280/290.

Dont double post! Looks messy. More so when what your posting reads like a free google translation.

I didn't like warhead. For me I loved the first half of the first Crysis because of the freedom you had. You could go stealth and pick off enemies with a sniper rifle or go in with kamikaze jeeps and blow s**t up.

Warhead's only direction is to blow stuff up. But I found the enviroments didn't have the same complexity of the first one and it wasn't as much fun- somehow everything seemed restricted. They also increased the number of spawned enimes which meant you couldn't just explore without being seen alot of the time. Go with crysis. I don't really play crysis onine (My computer can't handle everything on high/very high in multiplayer and I refuse to drop it to medium) so I have no interest in crysis wars but from what I gather it the same.

If you have already tied your CD key to your steam account then it cant be used again

Look at your games list. Is it there. You may want to delete the game and then reinstall it. If your game is under your games list then you dont have to worry about loosing it as it is there for life :)