I'm kinda jealous. Aside from standard military issue, I haven't experienced much of the other weapons. Honestly the M-4 carbine is a classic favorite I guess you can say. If you know what your doing and can take care of it, it is a good weapon system. My goal is to own a M-14, and a 1911 .45cal.
hands down favorite squad weapon is the m240 Bravo heavy machine gun and my favorite is the Scar nice shot with low recoil and a nice big ole hole threw the enemy's chest