Yeah, I did it needleturn. It's a method I like the look of the finished product, and I'm good at it.
I cut the circle from cardboard, placed it on the fabric and roughly cut around with a 1/4 inch seam allowance. Then I tacked with lots of little stitches just inside the cut edge of the circle and pulled the ends so the seam allowance gathered over the cardboard. Then I turned it over (still holding the tacking thread tight) and ironed the snot out of it! :D Voila, perfect circles. A quick yank on one end of the tacking thread pulled it out, whip out the cardboard, and whack the lovely edged circle down on the fabric and sewed it on.
I did use fabric out of my scrap bin, so these blocks will be in the finished quilt.