Our house is fairly new to the xbox 360 having had an xbox for years. My 16 year old son and I (his 45 year old father) have been playing CoD MW2 for a while and now MW3 for a few days.
You might be wondering if the new version is worth it, as we were. Well if you have finished the previous campaign then you are ready for a new one. The new missions are very similar to the previous ones so if you liked those and you want more you are all set with this new game. The online gameplay has new settings/maps and new kill streak rewards. Being new they are different, however the whole idea is the same asw in previous versions. So again to make your judgement as to whether this game is for you follow the same maxim. If you liked earlier versions and want more of the same then this is for you.
Now on the off chance that you are new to CoD you neeed to know that it is a first person shoot 'em up. It is fairly graphic and I wouldn't recommend for pre teens or for playing close to bed time if you think it would affect your dreams (as it might mine to be honest). If you easily seperate game play from real life then this is just fun but if you want to fill your mind with wholesome images understand that this game is about killing other human beings.
There is hours of fun to be had here but it is very similar to what has gone before and whilst it is still full price I think those who can wait would be sensible to do so and buy this when the price is no longer premium.