Originally Posted by joxer 
I have to disagree with the party setup above. IMO the best setup is 2 snipers, at least one support and the rest doesn't matter.
2 Assaults with the best armor leading the way (run & gun one of the best abilities for first encounters) followed by 2 heavies following up on the damage of the assaults. One support for running around healing as needed during combat and rear fire/support and one sniper to finish off those hurt. I find this setup has worked very well for me.