We don't have many choices when it comes to thread selection, so I use what's available (mainly spun polyester imported from China). When someone has traveled down I have had them bring me the CT cotton spools and love them. We also are able to buy some nice embroidery threads here and they have worked well for machine quilting, especially the variegated ones. Regardless of the thread, what I have found especially useful is to use Sewer's Aid - that's always on my list of supplies for people to bring down!