Honestly, I think all of those bands are overrated, as well. People always get mad at me for saying that, ha ha. But Floyd still one of my favorite bands, not the stuff they play on the radio though, I'm talking the Rummage and Piper at the Gates of Dawn stuff; basically their really crazy stuff. But as far as the other two bands you listed, yes they both are VERY overrated, especially AC/DC. I feel like every guy I know loves them and I don't see why, yes they're good but they're not that great. Led Zeppelin is also another rock band posers LOVE, don't get me wrong they were innovators of their time, but they're overrated as well. I mean seriously everyone always overlooks The Kinks, Pro col Ha rum, Deep Purple, All man Brothers Band, & Cream. Those are some of my fave bands!
But, you should listen to each band's lesser known stuff, it's always BETTER!
Listen to these songs:
AC DC- Long Way to the Top, Touch Too Much, Jailbreak, & Whole Lotta Rosie.
Pink Floyd- Careful with that Ax, Eugene, Shine on You Crazy Diamond, Jug band Blues, Candy and a Currant Bun, the entire Animals album, Goodbye Cruel World, See Emily Play, Learning to Fly, Sisyphus Part 4....etc.
Led Zeppelin- Whole Lotta Love, Immigrant Song, Custard Pie, Trampled Under Foot, Dazed and Confused, Black Dog, Ramble On, & Fool in the Rain (yes they are all pretty well known, lol).