The ones that charge no origination or guarantee fees and discout their interest rates after a certain number of on-time payments and for automatic payment schemes.
There are others as well. Your school should be able to provide you with a preferred lenders list although they cannot specifically pick a lender for you.
I like T.H.E. too, no origination fee and recommended by my school financial aid officer (off the record, since he isn't allowed to recommend one lender over another).