I've just lost all respect for you.
I would say the PP-2000 is the best SMG. Most people use the AKS-74U, but every time I go engineer with the PP-2000, I rape. To each his own.
I don't know... I can't get the hang of AN-94. The XM8 feels the best to me. I know that statistically the AN-94 is the best, but there's something about the XM8's recoil that makes it super easy to use for me. It only works with the ironsights though, but the XM8 has awesome ironsights anyway while AN-94 has the worst ironsights. The XM8 is really easy to single-shot/burst with pretty much no recoil at all.
I've tried to use the AN-94 and M16 in short stretches, but always end up going back to the XM8.
After unlocking everything in the game, the setups I tend to use consistently right now are:
Assault:
NS-2000 w/ extra explosives
XM8 w/ 40mm shotgun + lightweight
G3 w/ extra explosives
Engineer:
PP-2000 w/ extra ammo
NS-2000 w/ extra explosives
G3 or M1 Garand w/ extra ammo
Recon:
NS-2000 w/ extra ammo + C4
I pretty much don't use medic anymore. I'll only use medic if I feel like racking up some quick points. The MG36 is too good and makes the game unchallenging.