I just got a couple of spools of #100 wt. silk kimono thread from Superior Threads. I really like it for piecing. It's like using a finely tuned instrument. Really nice. It was $11 or $12 a spool on a "try it" special (usually $17); but let me tell you, I wish all my thread was this silk stuff! Plus there is a lot of yards on that spool. For FMQ I use the #30 or #40 rayon or poly---however, if you want the quilting to really show, the cotton heavier threads and variegated ones are a good product.