I'd have to place my vote for Fleetwood Mac's John McVie and Mick Fleetwood.
As far as drummers go, I'd say Brad Morgan from the Drive By Truckers is the most essential member of that band. I don't think the Truckers would sound nearly as good if it wasn't for Brad.
I have always been partial to these guys as a rhythm section (all 4 of them, really):
Would never call one the "best" and probably don't have one favorite, though. Too many great ones.
John Entwhistle/ Keith Moon
Ginger Baker/ Jack Bruce
A bass player from a pretty strong rhythm section just passed away last week. Jackson and Dunn were the epitome of the self effacing rhythm section.
Besides the ones mentioned, I would include Bootsy Collins and Jabo Starks from James Brown's band in the mix as well.
absolutely [felt that some should affirm these]
Well know in Boston, should be elsewhere.
The Hodges Brothers from Hi Records. Laid down the grove for Al Green, O. V. Wright and so many more.
Yessir, indeed! Crazy that Memphis produced both this rhtym section and Duck Dunn and Al Jackson, as rudyjeep mentioned. Also shout out to Roger Hawkins and David Hood from Muscle Shoals, not too far down the road from Memphis.
Stevie Ray's band Double Trouble has to be up there....Chris Layton on drums and Tommy Shannon on bass.
Another stellar team is Pete Trewavas and Ian Mosley of Marillion.