Oh my. This topic has been hashed out so often. A search will keep you entertained for quite a while. There are three broad categories of recomendations: 1) beam wrenches 2) clicker or electronic wrenches and 3) "I don't need no stinking torque wrench".

My personal preference is for beam wrenches as they are low cost, adequately accurate and stay in adjustment or are obvious if they have been damaged. I have both Park and Sears Craftsman models. For bike use you need a 1/4"-drive low range wrench and either a 3/8" or 1/2" drive for high torque requirements.