Really not much to offer in single player experience, but the multiplayer will get some people hooked.
The single player in Call of Duty 4 is short and boring. You fight through dozens of intense battles. You play as two people in this game. A British soldier and an American soldier. The British levels take place in Russia mainly, and the American levels lake place in the Middle East. When I say Call of Duty 4 is short I mean it is short. The single player only takes 5 hours to get through, and has pretty boring missions in my opinion, but some people will like it better than others.
The graphics in Call of Duty 4 look amazing. The environments look real, the people look real, and the weapon models look real. I would have to say that the PC version may look a little better than the Xbox 360 version, but the differences are minor. Still Call of Duty 4 is an awesome looking game.
The sound in Call of Duty has always been amazing, and Call of Duty 4 still has that great sounding sound. Bullets wiz by your head, and guns sound realistic. Do not forget the explosions. The explosions in Call of Duty 4 sound amazing.
The main reason why you should by Call of Duty 4 is for the multi player. This games multi player is a decent multi player experience. There are a bunch of different game modes and a bunch of weapons and perks to unlock. Some of the perks are last stand which allows you to pull out your pistol right before you die. Another perk is were you drop a grenade right when you die. The nice thing about the Xbox 360 version is that you can invite friends and you do not have to go and update you punk buster, or patches for the game. The bad thing is that the PC version has dedicated severs and the Xbox 360 version does not, so some of the matches can get a lot of lag. Over all Call of Duty 4 is a good experience, that will scare some away but keep other coming back.
There are only a few differences between the Xbox 360 and the PC versions of Call of Duty. I think the mouse and keyboard controls work better for this game, but if you are a Xbox 360 owner and you are a fan of the Call of Duty games then you may want to pick this game up. If you don't like Call of Duty then stay away from this game.