I have played the previous games in the call of duty series, and in my opinion this is the best one yet. It is a vast improvement on Modern Warfare 2 as the multi-player game play is now much fairer due to the more balanced weapons, perks and kill streaks.

Firstly, let me talk about the multiplayer part, as this will be the main reason that most people will buy the game. There is, as always, a large variety of guns and weapon attachments which can be easily customised to your personal preference in the Create a class mode.
The maps have been well designed and are very fun to play on. There is a new game mode called wager matches, where you bet your cod points (which you earn through playing the multiplayer part of the game) and compete with 6 opponents to come on top of the scoreboard.
My only concern with the game is the connection issues, about 1 in 4 games you play will either lose connection with the host and which leaves you waiting for about 30 seconds to a minute before you can start playing again or lose connection completely and send you back to the lobby ending the game half way through. This can become quite frustrating however I do feel that the gameplay more than makes up for this.
Another great addition to the game is Zombies. There is a noticeable improvement from the zombies in World at War, with more weapons and bigger maps it is a much more enjoyable experience.
Finally the single player on Black ops is excellent, I have not yet completed it but what I have played of it I found to be very fun and felt it had a great story line.

Overall I think that this is a great game and I highly recommend it to anyone who has enjoyed the previous games in the series.