Leggings are fabulous. Leggings with holes in the bum are not. Leggings that show the color of your skin are not. Leggings that show your fat deposits are not. And leggings that fall apart after a few washings are not. You can skimp and buy H&M, Target or BP leggings, but your best bet is to buy quality leggings that last and flatter your body.
If you prefer thin fabric leggings, but want them to last, American Apparel is a great resource and I have noticed that Forever 21 gives you some bang for your buck. If you want a thin legging that can last and hide some leg imperfections, Danskin is your place. Traditionally a retailer for dancers, Danskin provides high quality leggings that anyone can wear in both supplex nylon, which has a bit of a shine, and a cotton-polyester blend that looks like a more traditional leggings versus a work out legging.
For those that want a thicker legging that can hold you in a bit and smooth your leg I recommend Two by Vince Camuto and Lyssé. I particular like the Two by Vince Camuto for the line down the back of the leg. It adds style.