Malcolm came up with all their great riffs! It takes pure genius to boil things down to a simple but great riff.
Rhythm guitar, a dead art. After Mike Bloomfield, Eric Clapton, Jeff Beck, Peter Green, and finally Jimi Hendrix became the model for guitar playing, no one was content being a mere rhythm guitarist anymore (except John Lennon). Malcolm was the best!
+1 Bdp24

Nile Rodgers is a great rhythm guitarist but interestingly he actually made a career out of it - producing music with great vibes...

Jimmy Page could play lead and rhythm equally and did so with amazing feel.

Hamish Stuart of AWB was amazing rhythm guitarst too. Jerry Garcia and Bob Weir awesome too.

Sad news, another great one.   RIP.  

As far as the art of rhythm guitar don't forget about Keith.  Built a 50+ year band out of it.  
The list of excellent guitar players is extensive.

Style and ingenuity mark them as competent, special or genius.

One more ends his run and thankfully the repertoire left us is remarkably deep.

The loss is significant. AC DC was and is a major player in Rock & roll and elevated the bar to which other’s are going to be held for some time to come.
 Rest in Peace.

Robbie Robertson has said he used the playing of Pops Staples as his model for his playing in The Band. Robbie’s guitar "song parts" (as apposed to solos, the abilities at which being how most people access guitarists abilities) are supremely musical. A few more great rhythm/lead players are Steve Cropper (Booker T & The MG’s), James Burton (Ricky Nelson, Elvis Presley), and Albert Lee (The Everly Brothers, Emmylou Harris), all Telecaster players (as was Robbie on The Band’s first two albums).

Though commonly considered Hard Rock, I see AC/DC as a pure Rock 'n' Roll Band, the ultimate realization of Chuck Berry. It speaks to the teenager in me, even at 67!

Malcom also played with a relatively clean tone without distortion, just the right amount of natural overdrive plugged directly into a Marshall tube head.

Yes, Steve! Just enough "crunch", but not too much. Maybe it was those Gretsch guitars Malcolm preferred. Gibsons can easily sound too thick, with too much sustain. The best rhythm guitar sound I ever played with in a band was a Gibson Les Paul Jr. plugged into a Fender Deluxe Reverb, cranked up just enough to give it "bite".

A great scene in "Hail Hail Rock 'n' Roll", the documentary Keith Richards made of Chuck Berry, was the one on stage rehearsing for the live show. Keith is trying to help Chuck with his tone, and Chuck is having none of it. Chuck actually likes the horrid, overly-distorted sound he is getting out of his guitar and amp, and doesn't care what Richards thinks. Keith ends up feeding a signal from Chucks guitar down into the basement of the concert hall, where he has set up another amp. THAT amp sounds great, and is the one Keith recorded, I believe. He may have also sent the signal from the mic on that amp back to the house P.A., unbeknownst to Chuck!

Gretsch White Falcon - love the tone - darn heavy though!

National Tricone resonator - great for slide 

Rickenbakker for that jangle sound

I just love tone, attack, sustain and crunch 
Three great guitar sounds, shadorne! I’m working with a guy now who plays a White Falcon, and it sounds just fantastic. I knew a guy who had a Rickenbacker 360 12-string, and that darn thing was impossible to keep in tune. Fine for recording, but not live shows. Petty could do it, but he had a guitar tech. Rock Stars can afford one, but not mere working musicians!
R.I.P. Malcolm. Rock solid rhythm guitarist. Only a few weeks after his elder brother, the great George Young passed.

Another great Rhythm guitarist not mentioned, Tom Fogarty. What a great Rhythm player!