Definitely my favorite of all Zeppelin albums. It's maybe not a "perfect" album from start to finish but it has the perfect sound on every track. The balance of bright guitars and thunderous bass/drums, I don't know man. The production quality on Houses is just the absolute best I've ever heard on a rock album. Certainly some of my favorite songs are on here - The Song Remains The Same, The Rain Song, and Over The Hills and Far Away make one of the best combinations of three songs to open an album I can think of. The others are just super cool, even when they fall a little flat on composition, you get to just listen to an insanely talented band just groove and be their badass selves. And then after that you get No Quarter. Goddamn.