There is a fantastic post up on Bleeding Heart Libertarianism about the reasons many philosophers reject utilitarianism. The article also draws a distinction between consequentialism and utilitarianism. Good stuff.
Consequentialism is best understood as a family of moral theories, united in the agreement that consqeuences alone determine the rightness or wrongness of actions. Utilitarianism is aparticular type of consequentialism that specifies the kind of consequence that matters – not wealth, not human achievement, but utility. It follows that utilitarianism is necessarily a more controversial theory than consequentialism.
The second point, and the more important one, is that believing that consqeuences matter for moral assessment is not enough to make you a consequentialist. Any plausible moral theory is going to hold that consqeuences matter at some level. What distinguishes consequentialism from other moral theories is its claim that consequences are the only thing that matter. This is a much stronger and much less plausible claim.