I use Bottom Line thread in the bobbin and A&E Signature thread on the top. The reasons behind this decision are multi faceted.
Bottom Line thread is a smooth poly thread that is not only strong, but there are no fibers for the top thread to catch on, making it an ideal thread to use with a cotton.
Signature thread is a cotton wrapped poly. This is my thread of choice for tops because it combines the strength of poly with the look and feel of cotton, allowing me to match thread to a color of cotton more closely.
Both these threads together make for a sturdy stitch, without getting hung up on each other, allowing the machine to move continuously with minimal breakage along the way.
There is a wide variety of colors available to be chosen from, to best suit the colors and patterns of your quilt.