Some of my setups:
VKS w/ Extended mags and Thermal.
MP-443 Grach w/ Armor-Piercing
Throwing Knife.
Sleight of hand
Sitrep
QuickDraw
Gambler
Satcom, Dog, Trinity Rocket
That is my camping class. I can easily watch my team's flag, and B at the same time on some maps. As long as 2-3 other people on my team are runners while I defend, it's easy.
My class for non-camp friendly maps:
CBJ w/ Red dot, Muzzle break.
Frag Grenade
Sleight of Hand
Hardline
Sitrep
Gambler
Resilience
Satcom, Dog, Trinity/Juggernaut.
Some things I find useful:
When playing with a coordinated team, don't cap your side's flag until someone dies, or if there's a rusher on the enemy team, you kill him when he tries to cap your side. Free revives, no penalty.
Have 1-2 people run sitrep and point out explosives, and if they have satcoms.
When it's 1 v 1, make your way to one of their flags. Wait til they attempt to cap, then take their flag. They may have everyone back, but you do too.