Aurifil is wonderful, but "So Fine" by Superior is now my favorite. (They are really comparible, but "So Fine" is a bigger cone of thread. Plus, my bobbin holds doesn't run out of thread as fast.
My favorite colors are #487 "Helena" or #456 "Goosedown. They are greens that blend into anything... The only time I piece with another color is when I'm sewing really,really light colors. Then I use #402 "Pearl".
You can go to www.superiorthreads.com to check out their colors.