What do YOU want in a new wiring harness?

I have noticed that many new lamp sockets, molded plugs such as voltage regulator and stock electronic ign come with 6 to 10" leads already installed. What would be recomended or not to install theese to new wire.
There is also a ? I have of how to hook up to temp sending units and fuel sending units. What works for you?
(be nice) :)