It all depends on your level.
Call of duty , because it burns your will to live to the outside world.
Yes you can unlock extra perks on call of duty four but you have to be playing on live and gain ranks. to do this you must win round with 1 or more kills.
There is no call of duty 6. call of duty six is black ops.
Yes. Cats with exposure to call of duty live 1 million years longer then cats with no exposure to call of duty.
Call of duty 4 Call of duty world at war Halo 2
No, you can not download maps for call of duty five without being on xbox live.
it depends where you get it
yes
If you do not have Xbox live, there is no need to have Call of Duty Elite. The COD Elite gives you a huge data profile about your online stats, matches etc. If you do not have xbox live, there are no stats to gather. The Call of Duty Elite will have a yearly cost, this will be a separate payment from Xbox live.
As long as your xbox 360 is connected to the internet and you have xbox live GOLD membership then yes you can play on xbox live with call of duty
yes
You have to have Xbox Live if you have an Xbox