What games should I get?

I would insist you get Modern Warfare 2. Since it hasn't came out yet you and your brother will just have to be patient. If you haven't played the first Modern Warfare that's ok. The first week is going to be basically who can be the first to become number one in the world (lol). After that week everything will calm down a little bit. Call of Duty is one of Playstation's top selling series for a reason. Many people find this series to be one of the best first person shooter games on the console! I hope this helps you! :-)