In a recent 2v2 team game, my Zerg partner was the type of player who liked to sit back for a bit and macro up, whereas I advocated early aggressiveness. Whether I played Terran or Zerg, aggression seemed to pay off - the opponents were thrown off their game, assumed that we were going to keep sending units, so when we backed off for a bit and pumped economy, they would be preparing for an attack that could come any second, but never did, thus setting them behind economically while we surged ahead.
What's sad about some of the greatest resources on the web, where Diamond-level game-casters tell us all about great strategies and show top-level games, is that there's really nothing I've found (so far) for team games. It seems that the focus is all on 1v1.
The main problem with 2v2 is that it's possible to completely overwhelm an opponent by about the 25-food mark simply by having you and your partner send 3-4 units each to one opponent's base, especially if they are Zerg and can't wall-in. To anticipate this early aggression, you also have to have minimal defense, meaning you're probably going to have to make some attack units regardless, sacrificing economy. However, if you make attack units, don't attack, and your opponents don't attack either, you are behind on economy and you're eventually going to get rolled over by a larger enemy army. Thus, early aggression gives you both scouting, defense against their early aggression, and keeps your economy even with your opponents', and might even help you win the game.