I'm not usually big on MMOs, mainly because of subscriptions. But there is one very close to my heart that is subscription free. Global Agenda is a third person shooter MMO featuring PVE and PVP mission. It's a ton of fun and has quite a large amount of weapons and skills among it's 4 classes.
As an Assault, you can either become a tank to protect your allies, or become an unstoppable force of nature to wipe out the other team.
As a Medic, you can either be a TF2 style healer with protection buffs for you allies, or you can be a poison master and make the other team suffer with PAIN!
As a Robotics, you can build sentries and buff station t