Off white would show up the most. I've done both of the others. I personally like the look of crisp white slightly more than pastel on white/pastel, but that's just my personal taste. Either one would blend equally well and look good. When I'm trying to decide -- if I have both threads -- I will "puddle" some thread on the quilt. Just unwind maybe 18-24" onto your quilt top and decide which one you like best. You really can't go wrong with any of the 3 choices.