Wow, so many opinions and some really good logic, too. One topic not mentioned here is that not all cotton is the same. Certain cotton threads are made of Egyptian cotton, long staple fibers. These make a smoother thread with fewer fuzzy bits that can clog up your bobbin area. Recently I was quilting on my Sweet 16 and noticed that I could actually see tiny fuzzies on the thread as it passed down to the needle, and I brushed out little clumps of fluff when I changed the bobbin. It was a sample of Superior Omni, which is "poly wrapped poly." So not all fuzzy thread is cotton. I talked with a local shop owner/professional quilter who said he prefers Superior So Fine#50 for some quilting jobs as it has a smoother texture than the Omni and less clog factor. I bought a cone, so I'll get to try it next. He also explained the difference in fibers of some cottons, such as the Egyptian. He has been experimenting with an Italian made thread, but I don't recall the brand.