I'm not going to make any fans here, but I DESPISE Zep. Robert Plant sounds like he's riding the white horse perpetually, the instrumentation is incredibly overwrought (and not terribly interesting, seriously, what the fuck is up with that 3 minute noise/drum solo in Whole Lotta Love?), the lyrics seem like overgrown bluesy fever dreams, and worst of all, people have built them up to a level where if they had done anything short of making me want to base an entire religion off of their music, it would have been an immense disappointment. I vastly prefer REAL blues to this (I grew up listening to old blues and bebop, not some white boy psuedo-hippie 70's revivalist shit), and if I'm going to listen to old school metal, I'm going to listen to Sabbath. I don't rightly give a damn if they were pioneers, I hate what they did.
Playing no small part in this was that I was in a band that collapsed over a Led Zepplin song, and neither I or the guitar player could stay awake during this garbage. The drummer wanted me to channel Plant and do this stupid repetitive bass riff over and over (the song was Whole Lotta Love, by the way). I could do it, but the more I did it, the more I becan to hate that harsh, nasally sound and the baleful riffs that were sludging out of that song.
I agree with what one above poster said about Sabbath binging in more of what we know as metal with the tri-chords and low tuned instruments, heavy distortion, dark lyrics with cavernous meanings, ect.
Lastly, I digress that I like two songs and two songs only by them: Houses of The Holy and Stairway to Heaven, because those are classics. Everything else can fuck right off. I've tried and I've tried hard to like them, but I feel really only passionate hate for them.