Depends on what my partner is playing. If orc then probably Human and UD because I am always scared of a human towering me in team games and the UD can put great pressure on you while they tech to like a few frosties, shades are a bitch to deal with in team too. I hate those units in team. If my partner is UD then I'd say Elf and Orc HH/Hunts combo is hard, and if he's Human then.. Hard to say I love playing with human players in team, probably UD and Human together because once again the shades being used and human can get morts or something and I find my base is usually gone if I play it stupid.