mermaid

My cat quilt--applique..it's been finished for several weeks and I have been putting off quilting it because I just can't decide how to do it. I do not want to hand quilt..just finished a BIG Q size and I'm tired. Want to machine quilt if I can come up with a simple pattern or should I just SITD? And should I use blk thread or select a variegated? I would appreciate all the ideas put forth by members before I settle down to actually working on it. It's only a good size lap quilt and I started it for charity..but I love it so much and I'm a cat lover too, so I want to keep for myself. Thanks to all.