A friend had been telling me how great On Gossamer panties were for years, and I finally picked up two pairs (one in the bikini style and one in the boy short style)a couple of weeks ago when I found them in a local store on clearance.  Both pairs really are as fantastic as most reviews say!  I think I do like the bikini better since the lower cut sits better on me.  The mesh fabric is so light that you don't even notice them, and they really don't leave panty lines under clothes.  Additionally, the colors are fun and cute, and they wash really well if you put the machine on gentle cycle and lay them flat to dry.

Since I tend to have a bit of a "bubble butt," they have ridden up on me a few times, but overall they stay put.  I will definitely be picking up more of these.

UPDATE ON 7-15-13:  I wanted to update my review to say that these are my all-time favorite panties!  They stay in place over my large tush, and haven't been riding up at all.

Also, I've purchased the pattered mesh versions of these and also the cotton ones, and the plain-colored mesh ones are the best.  Both the patterned mesh and the cotton ones ride up on me, but the regular mesh ones stay in place.

These are expensive, but if you can get them on sale, they're awesome!  Heck, I'd even pay regular price for these -- they're that great!