I found one stab at a definition for the Drake Equation at http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html. It claims that the equation was developed "as a way to focus on the factors which determine how many intelligent, communicating civilizations there are in our galaxy." And since I have not heard of any "intelligent, communicating civilizations" other than our own as of yet (and do not look at all good in tinfoil), I do not see how I could be misinterpreting it. The final, crucial, stated condition has not been proven, therefore it is bunk.
Don't get me wrong - I would be happy if ET were found someday. But he hasn't been so far, and I do not believe he ever will be.
Is it that you don't think that the factors in the Drake equations actually have values, or that you don't think that the product of those values, once measured, would yield the correct answer?