Ah HECK! I use whatever my hand hits...usually that is a grey Masterpiece on a BIG cone for piecing. Its not cheap, but I usually only use one of those babies a year...with one in stock JUST in case I run out at 10 pm and CANNOT stand to stop sewing. (usually at 10 I'm passed out snoring in the bed...sorry for the mental picture!) For quilting, my long arm is happy with most everything. For the most part I use Permacore or Omni, both poly wrapped cottons. I like the weight and the sheen. I have some silk, Glide and Magnifico to try. The Glide and Magnifico are both polyesters. I say use what you have, what you like and what is in the budget. Just my humble opinion. (No quilt police allowed...)