Hi Mary Jo,
I use Superior Threads. I love King Tut colors, but it's a little to linty for me. I've since switched over to their new Omni beautiful colors and it's not as linty. But for thinner threads I use So Fine. Almost all the threads I use I match with Bottom Line in the bobbin.
I also enjoy using Isacord (embroidery thread) and Fil Tec. Both have a beautiful sheen to them. Hope that's helpful.