"Del-A-Lum" or "Delrin" (solid bushings with nylon sleeve). They are basically the same it's just a trademark thing.
These three companies carry them. These have no deflection and almost zero drag unlike rubber or poly. These are what the racers used to use. But don't let that scare you... they won't degrade your ride, they're greasable, and they'll out last the rubber or poly.
Herb Adams does not recommend polygraphite for rotational applications such as control arms. Once the grease pushes out after a few weeks it will allow the sleeve to bind, which promotes sqeaks, moans, and does not allow the suspension to move smoothly.
Check out their sites, read the info. and decide for yourself. They are a little more expensive, but you're only going to do it once anyway (unless you do poly and it sqeaks!)
