I like Essentials threads from Connecting Threads. I have it in a bunch of colors and it is wonderful for quilting and piecing traditional cottons. I have found that Aurifil does better on batiks for piecing. For quilting I also like King Tut and Superior. There is a wholesale-to-retail online store called J. Hittle that has fantastic prices on threads and things like rotary cutter blades. Our quilt group places an order together a couple of times a year to save on shipping and split up large orders. We did one a month ago and all ordered rotary cutter blades, each of us getting 10 blades for about $1.50 each. A real bargain!!
http://www.jhittlesewing.com/visitor/index_jhs.html