I do use lots of white for my backgrounds! I've also used various shades of gray like light gray, slate, and charcoal. I have experimented a little with using a color. I've done a deep rust (for a string geese quilt) and a soft pale green for a quilt with various florals.
I have not braved something bright yet like pink! Or bright green! Or Yellow! But I've seen quilts with these and they are always unique and stunning!
My current trend is experimenting with various low-volume backgrounds for a scrappy look!