One of my favorite organic looking threads is seagrass. I love the flat broad stitch you get when stitching with it.
www.sewingparty.com Cecile the owner has a great eye and the store was filled with a wonderful selection of eclectic fabrics. She made us feel very welcome as we nested in her classroom for two full days.
I hope each one of you enjoy the journey of stitching on your samplers.