For getting a really good fine line on dark fabrics, I have been pleased with the Clover White Marking Pen. You can't see the line until the "ink" dries, but then it shows up really well. The really cool thing I like about it is that you can get rid of the marks easily with a hot iron (steam or just heat) or with water. :shock: With that said, it is a fairly new product, and I have no idea what will happen with these chemicals in the fabric in 100 years, but that is not an issue for me, and I always wash my quilts when I've finished quilting them.
http://www.clover-usa.com/product/69424/517/_/White_Ink_Marker
I also hate the way the blue wash-out markers don't seem to last very long. I have had success for years using the CRAYOLA WASHABLE markers. They come in lots of colors, and are lots cheaper. I always take special care to remove the marks when I'm finished, and like the blue markers DO NOT expose the marks to heat.
For any quilt that I have marked, I put them in a washer full of tepid water for an hour our so, then spin all that water out to remove the water soluable chemicals. Then I refill the washer and use Quilt Soap (Orvus Paste available at the farmer's co-op!) to wash it, then dry it flat to block it. If it's a cuddle quilt, I often throw it into the dryer, which makes it softer, but the heat does cause some fading.