This is a really fun World War 2 shooter that is free to play. It is multiplayer only, but it is a really good game. I suggest trying it out. I myself play on the Enemies of War server with 2.55. Currently there are two versions of the client available, 2.55 and 2.6. You start with installing 2.55 and you can optionally upgrade to 2.6. Some servers are for 2.55 and some for 2.6. I have heard that 2.6 is much harder to play. The game is easily found on Google, just look for it. The game runs natively on OS X, Linux, and Windows.

Ah I used to play this game, its a lot of fun I tell you. I've moved on to more modern games however such as COD4, Age of Conan, and Left 4 Dead (as soon as they are released).
I also play Team Fortress 2 which is a really fun and addicting first person shooter made by Valve.

Quite a fast pace gaming, and has a lot of role playing game features which I didn't like. Someone who's a high level then you would have better weapons. Which isn't balanced and quite annoying.

The weapons stay the exact same. You just get better accuracy, more ammo, and other things. Like Akimbo pistols. Course I only use pistols when I'm using a weapon like a Panzer and I need to do a close up kill. Or I'm out of ammo. I enjoy the roleplaying parts.