The best conductive thread that I have used is no longer manufactured.
Which means I am conserving my supply and purchasing a 1 pound cone of with a resistance of 15 ohms/foot. The diameter of this thread is larger so I use a size 24 chennile needle. It also has a bity tooth to the thread surface so I recommend waxing it before hand sewing.
If you are teaching or using a lot of the thread set up an account and purchase wholesale. You will save a bundle!
UPDATE 23 FEBRUARY 2014 – the manufacturing process for Silverell’s 234/34 has changed and I can no longer recommend this thread for eTextiles.