Nice image. The best ones using a ring flash are the ones which don't look like you used a ring flash! (like this one)
I really like using ring flashes, I have an old (practically antique) Vivitar one from the 1970's which is still going strong. They really do a very good job at providing almost shadowless illumination.
Its been interesting playing with this thing. I'm not sure it worked that well in this scenario.
There was some good light today. I got a chance to snap a couple with the 1ds. So you can see how that flower looked without the color toning in the first one. Anyway, I'm really liking this camera.