I use gray for piecing unless the backgound is black or white. Then I use black or white. It saves buying a lot of different colors. If I'm doing top stitching I may need to buy something to match. Then of course there are all the differnt colors of embroidery thread that I have to buy. My husband bought me a thread chest full of embroidery threads last year for Christmas. Actually that is now two years ago Christmas, with this being 2011.

I use white, black and gray.

mother goose for medium/darks, and dolphin gray for lights!

Beige, Gray, White and Black for piecing

Usually neutrals for piecing. But if I have a perfect color match, I will use it.

I guess I will be the rebel one on this one. I like ti piece with colored thread. I try to match my predominant color. Of course, I like to use a lot of solids in my quilts sometimes, and in that case i can match it well. Black or white is too obvious when you are sewing on yellow, for example.

I use grey or beige
Colors for quilting. I tend to like the variegated thread For quilting.

I have so much thread I cam most of the time color match my main fabric. Hubby doesn't want me to buy anymore anyways.

I am with the majority. I have black, white, beigh, brown, light gray, dark gray, and that is about it. You don't see the seams anyway so why bother matching exactly? And I also like 50 wt for piecing and I like 40 or 30 for quilting.

Beige/tan mostly, unless the fabric is really dark. Then I use black or dark blue (sometimes it depends on what I have loaded on extra bobbins!).