There is no one "all-purpose" torque wrench for bike use. You really need two; a low torque 1/4" square drive (typically 0-60 in-lb, 0- 7 N-m range) and a higher range 1/2"-square drive (typically 0-150 Ft-lb, 0-100 N-m) The first is used for things like handlebar and stem clamps and the second for bottom brackets and crank bolts.

I'm partial to beam type torque wrenches. They are less expensive and more rugged and can be "recalibrated" as FBinNY described by bending the pointer back to zero if needed. "Clicker" wrenches have a big advantage if you are working on bolts where you can't easily see the wrench, such as automobile applications, but that never applies to bikes. Sears Craftsman line and Park Tools both sell good quality beam wrenches and even Harbor Freight has adequate ones.