If you're not putting any pressure on the line, eg. just draining the kettle into the carboy, a hose barb works just fine. If you're going to be putting any pressure on the lines, like using a pump to recirculate, the quick disconnects, camlocks, or tri-clover clamps are all popular choices. On my BIAB kettle, where I just drain, I use a barb, but on my recirculating direct fire mash tun, I use camlocks.