I've used Coats & Clark dual duty all-purpose thread (the cotton covered polyester stuff - there is something different available now) for machine piecing for almost 20 years and had no problems with it "wearing out" the seam lines.
I used to be "matchy-matchy" - but for piecing discovered that as long as the stitching doesn't show when I try to pull apart a seam, I'm good to go.
When piecing light to dark, I think I try to go for a "medium" colored thread.
For almost all medium to dark colors, I've found that sort of a greenish gray - about the color of easter egg dye when the colors get all muddied up - works well for just about everything.