A torque wrench is a good investment, but make sure you get one that has the range you need. Do a survey of the fasteners and take note of the recommended torque. As with most tools, price is proportional to quality. Those who wrench a lot often don't use torque wrenches because they've developed the feel with experience. Personally, I use one. I've been eye-ing this wrench and it come with 6 hex bit sockets:
http://www.artscyclery.com/descpage-SHTW.html

Also, these hex bit sockets adapt the square drive on a torque wrench or socket handle to the fastener. You'll need to match the drive of the wrench to the drive of the socket. I use these hex bit sockets almost exclusively in my workshop. When mated to a socket handle or driver, it makes wrenching nice.
http://community.craftsman.com/Craft...-Drive-reviews