I play around with a macro lens from time to time. Shot this spider in my garage. DOF is a bit of an issue at a distance of about 14". Next time I may increase my working distance then crop. I don't have a ring flash but I did use a Nissin Di866, handheld (in commander mode), with a Gary Fong diffuser. From what I remember of this little experiment, I got more keepers when holding the flash off to the side than I did when it was pointed straight on the spider. Not a work of art by any means, but something I would certainly attempt again and a technique I'm assuming I could improve upon with a little trial and error.
Wow, your results are pretty awesome!
I've also tried using flash with my macro lens, and this is what I got.
I shot this with just my pop up flash on the D40 and a 105mm macro Nikkor.
I'm surprised that I didn't get a huge shadow, considering how huge the 105mm is.
I never went back and followed up on it, partly because I get eaten alive by all the mosquitos in my backyard.
I'm also curious about adding a SB-700, just because I can. :D
Might be a little gift to myself later on.