Welcome to the Quilting Board!
As is often said ... it's your quilt, do what you like ... there are no rules!
Some will change the threads for different sections of their quilt.
Some want the thread to disappear into the quilt, thus matching the colours.
Some want the thread and thus the quilting to be quite noticeable, and will choose a contrasting thread.
Sometimes when you have both dark and light fabrics in a quilt, a variegated thread will do the job.
Just as you audition different fabrics, audition your thread.
Pull off a few feet and let it fall randomly on the quilt top, to give the effect it would have, if quilted in place.
Another consideration is the weight of the thread ... a finer thread will be less noticeable than a coarser one.