My favorite has to be the saiga 20k. It has a very unique role of being a longer range shotgun. I find it challenging to use and fun. It goes boom boom boom. The reload is nice and it has a very tight grouping, and I think that actually puts it at a disadvantage as most of the pellets will miss if you are really close with the current lag. If you cant get one of those yet its very similar to using a desert eagle, but the accuracy doesnt change when you crouch. I like the ak style look of it too. With the m4 and m3 out, it has become rare to see on the battlefield and rare guns are always a plus for me.
So what are your favorites?