Led Zeppelin are sexier, bluesier, and folkier... their music has the groove, the pull, and it's interesting and elegant.They're so cool and I gotta say I like ALL their albums, which is something that I can't say for almost any rock band (actually, now that I think about it, could it be they're the only ones I can say this for? wow... )
I totally love Black Sabbath, but the "right" black sabbaths...meaning from the very beginning until Mob Rules with Dio...and then a big jump until 13th, which I really dig.
The stuff in between, Nah.
But in their right albums they created a sound and an impact that I still love completely, and the lines of Butler are one of my main inspirations on the bass and reasons why I picked the instrument in the first place.
As for Deep Purple, kinda same story in the sense that I love the really good albums by them (and they're not many but still) and the masterpiece Live in Japan, and that's it.
But one thing is for sure, Ritchie Blackmore is amazing, and what he did with Deep Purple and in Rainbow (first three albums with Dio) is golden.