First, I want to add another tribute to Chili onto the pile. His collections have embodied, to me, a true celebration of human sexuality. His sites are fun, deep archives filled with real interesting content, and I find a lot of it due to the liberal smattering of PE content. Though, like some of the other posters, PE alone doesn't really interest me -- it's the mix of PE and BE that really makes things "pop".
Why are they the best team since peanut butter and chocolate? Perhaps it's because this stuff is our heathen age's modern sexual mythology, and the images we produce and consume are like high-tech versions of centuries-old hyper-endowed African fertility dolls, or one of those ancient Indian temples covered with tantric carvings... Unreal, almost-divine imagery filled with powerful symbols of copulation.
Good luck with the PE Archive -- it's a great idea. Let us know how it's goin'!