I like to use the variegated thread on most of my quilts. I think all of the color changes distract the eye from my mistakes:-)

You don't need quilting thread, but if it were mine, I'd use a red, white and blue variegated. Rayon thread seems to less strong that cotton or polyester, so that's a consideration, too.

I like to use variegated thread when I quilt my scrap quilts. I think it looks great.

Irishrose,
Rayon thread won't hold up to much washing when used for machine quilting. I made that mistake once, in a fancy jacket that I made for myself.
Sharon