Consolidating Student Loans - Good or Bad Idea?

I have a mess of loans through AES. I am able to pay them all at once online through the AES website. Would it be best for me to go ahead and pay that way, or consolidate the loans? What are the pro's and con's and what is the cheapest way out? It says for most of the loans that after 24 and 36 consecutive on-time payments that there is a rate reduction... how much of a reduction would it be and would this save more than consolidating the loans? Should I consolidate through AES or another company?