I really like the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK099&P=ML]screw lock[/link] connectors because they make it very easy to setup the plane, but they are a little pricey. I use a little Tamiya thread lock on them and tighten them down good, never had a problem. Otherwise I use whatever comes with the ARF or whatever I have on hand. The cheapest route is no connectors at all, just a Z-bend at both ends. That's the most difficult, since you have to get the length just right when you bend it (not adjustable), and you have to pull the servo arm off of the servo (or the control arm off of the control surface) to connect it.