What Mass Effect Decisions Could Change the Sequel?

Having already played and reviewed Mass Effect 2, OXM UK has published an article that breaks down many of the decisions we made in Mass Effect and how they might affect us in the sequel. As expected, spoiler warnings apply:
Helena Blake - One of the Citadel's side-missions sees Helena Blake ask Shepard to take down the two criminal leaders of the syndicate she's part of. She argues they've gone too far and push beyond the petty crimes she was prepared to tolerate. Having completed the mission, you can then kill Helena Blake after she resists arrest or convince her to walk away. But what about if you let her take control of the crime syndicate? Will this come back to haunt you in the sequel?

...

Council - After having several run-ins with the Council throughout the course of Mass Effect - in particular, the snarky turian - you had a chance to influence what happens to them at the end of the game. Sacrifice them for a better shot at Sovereign? Or ensure they die in the attack? This will have a huge hand in shaping the course of Mass Effect 2. The former sees humans join asaris, salarians and turians on the council. The latter sees humans emerge as the dominant race. It'll be interesting to see how different the sequel becomes because of this decision...