For quality, Good Dyke Porn wins hands down. There is more hotness in any one of their videos than an entire adult book store. As I like my women with a variety of styles and shapes, their website is a Godsend. They even take the old "Did you order a pepperoni pizza" sketch and tie it town to the bondage table. I'm still wiping the sweat from my brow.
On the realistic side, we have Authentic Lesbian Erotica. It's not updated much, but the poster seems to be able to uncover actual girlplay that even I haven't seen. And this is from someone who spends way too much time surfing for it. But why doesn't the Lesbiana Mexicanas link work, goddamit?