I love the new runningskirts.com skirts! Of course, I wear the running skirt (brief) style, and the new cuts have been really great for me. I love the material, it's so lightweight!
I also have a skirt from skirtgoddess.com. It's the one with capris. I haven't run it it yet, but the fabric is a lot heavier...if that's what you're looking for, then definitely give skirtgoddess a try! A lot of people love the commitment style, which has shorts underneath. They don't work so well for me, so I have to stick with brief style skirts.
I also have a roller girl (girl shorties underneath) from skirtsports.com. It's a little big, because I was concerned that it would be too small so I switched to a medium. I think the small would have fit me just fine. For some reason I feel the most exposed in this skirt.
I've also just ordered a marathon girl classic from skirtsportsoutlet.com. It was only $12, so I thought I'd give it a try. It has briefs.
Ever since I heard about running skirts, it's become an obsession...I have 11 with one more on the way...I don't ever expect this madness to stop, as runningskirts.com keeps coming out with new colors I need!
ETA: I do have one of the old style athletic skirts. The fabric is VERY different...it's a lot heavier/thicker. It's a little big on me so I couldn't ever run in it. It's great for golf, though...