what is the best rock n roll song of all time?

I am of a similar mindset as those who grew up enjoying "classic rock". I agree that rock and roll is out of fashion right now and has been for some time. Hopefully, it comes back soon. Obviously, the greatest rock and roll song is purely a matter of opinion. I have seen many great suggestions on the thread already. I'll second the suggestions of Kashmir by Zeppelin (along with many of their other tracks), While My Guitar Gently Weeps (the Beatles - granted mostly George - with Eric Clapton - maybe the ultimate synthesis of organic rock star power on one song), Whipping Post by the Allmans (although One Way Out is a personal favorite), War Pigs by Sabbath (I may be old school but to me at least Sabbath is still the archetypal metal sound), with Born to Run and Freebird certainly being deserving of mention.

I'd add a few that I don't think I've seen yet - Crosseyed and Painless by the Talking Heads (a great guitar song from a normally restrained band), Baba O'Reilly or Won't Get Fooled Again by the Who (take your pick I can't choose one over the other), Money or Comfortably Numb by Pink Floyd (Comfortably Numb is definitely a contender for best guitar solo), Basket Case by Green Day (I thought I was still hip until I realized how old they are as well), Crossroads or maybe Sunshine of Your Love by Cream (there's that Clapton guy again), Fat Bottom Girls by Queen (feel free to substitute Bohemian Rhapsody I'm just partial to the guitar riff in Fat Bottom Girls), Games Without Frontiers or Shock the Monkey by Peter Gabriel (granted most people will pick Sledgehammer for him), Let's Dance by David Bowie (Stevie Ray Vaughn on the guitar), Roxanne or Every Little Thing She Does is Magic by the Police, Hot for Teacher by Van Halen, Satisfaction or Jumping Jack Flash by the Stones (although I'd prefer something from the Mick Taylor era - maybe ***** or Rip This Joint (edit - word that got bleeped was name for a female dog -sorry didn't mean to run afoul of service rules), and the list goes on and on.

I'll stay away from the second tier and obscure stuff for this list as I have to consider popularity and commercial success one aspect of the question, but I'm sure I could find other contenders with any number of great artists (Warren Zevon, Blondie, the Yardbirds (there's that Clapton guy again), Big Brother and the Holding Company (or Janis Joplin on her own), Robert Cray, Julian Lennon, Phish, Foo Fighters (their live tunes with Jimmy Page and John Paul Jones were so exciting if for no other reason than you could feel the lifetime moment of fanboys playing music with their idols), etc.

Rock and roll is definitely one of my few passions that I have not left behind as I've gotten older. What broke my heart was when I watched the Hurricane Sandy concert and saw a number of artists I've always admired and noticed how old and tired they sounded (at least to me). As an example listen to the song "Early Days" from Paul McCartney from his New album (that's not a typo that's the name of the album) (when CDs have breathed their last will it still be appropriate to call a disembodied collection of songs that exist only by a linked title on iTunes an album?). You can hear the age and deterioration in his voice. He's still clearly Paul, but at times in that song he really sounds like an old man. Again, this truly saddens me.

The world needs a younger generation of rock and rollers to come along and make it relevant again. I hope my kids get into it. So far, the 16 year old doesn't seem to listen to much music, the 13 year old likes some classic rock, but clearly needs something more attuned to today, and the 8 year old likes anything played on Sponge Bob. To think, my parents used to insult the Rolling Stones when I was a kid, now, you hear Brown Sugar on the oldies station. Sad.....