Although I have never really been a Led Zepelin fan, Physical Graffiti has some good (or even great) ideas, but the tracks are just too long. Nevertheless, as a collection of new material, outtakes and re-workings, it turned out to be very influential. You can hear Kashmir in just about everything, including Whitesnake's Love Hunter, Deep Purple's Perfect Strangers and Black Sabbath's Tyr. I always like the Led Zeppelin things that no-one else does, so Boogie with Stu is one of my favourite tracks on the album.
John Paul Jones's bass playing always stood out for me. Have you heard his Zooma album? Some of the ideas are not fully developed, but the bass playing is great.
John Paul Jones - Zooma - YouTube