I like Aurifil and Metrosene best but if I need a particular color, mostly for garment sewing or alterations, I will use Coats and Clark because that's what the store closest to me sells. For piecing I generally use Aurifil gray and have that on hand because I plan ahead. For quilting I always start with a new spool because then I know I will have enough. It seems like I do a lot of quilting in white. I usually use Metrosene for quilting and will stock up when it goes on sale.
I was shocked however when digging through my thread supply to find an older spool of Metrosene and one more recently purchased for a comparison. Both spools had a small amount left on them. The outside of the spool was the same size. The inside however on the older spool was considerably smaller meaning there had been a lot more thread on that spool initially. Not only has the price of thread gone up the amount of thread you get on a spool has greatly decreased.