I always go neutral...cream, white, etc.
I will warn you about Coats & Clark - it has created so much dust in my machine that I will not use it again. I prefer Aurafil, or other high quality threads. I usually wait until they are on sale at Joanne's (you can get them at 50% off) and stock up!
I consider my machine a major investment and almost like another child - and don't want to damage it with what I put in her tummy!