Ps3 Question I want a shooter fps or tps (third person) It needs online. I have $120 to burn. I want 2 games.?

I have Modern Warfare 2 and Uncharted 2. I am stuck between for Killzone 2 and MAG. Do many people play Killzone 2 and is MAG expected to have many players. Is online fun for those games. Put your psn id if you want. Thanks for answering. Thanks for leaving your id if you did. :)