Assault Rifles - They are not as punchy as pistols, and not as BRRRRTworthy as SMGs. Never been much of a fan.
SMGs - With -100% recoil mod, they become the ultimate "hold down left mouse button" and drill into enemy weapons.
Sniper Rifle (SVD) - I love these things, with an expanded ammo clip and the long range mod - they bring down enemies quick.
Magnums (Regular) - Never leave home without one. Capacity, damage and faction mods are a must.
Anti-Materiel Rifles - Tried using one, it was shit. So I melted it down.
Bottles - Decoy bottles serve as invisi-detection and mines, and explosive bottles are a good hand grenade option.
Rocket Launcher - Decided to max this out ASAP, and I am glad it did. One-shots most boss elites, has 3 charges at LV10.
Revelations 2's campaign was already worth the price of admission, but the inclusion of this incarnation of Raid Mode is what really makes the whole thing a sweet package. The only downside is a lack of matchmaking presence, but it just means that you'll have to manually get to know new people and make new friends for co-op. To me, the slight inconvenience of a more personalized community definitely has its own blessings.
Picture credit: notsodamndeviant@Deviantart