Pondering the greatest guitar riffs of all time

I started wondering the other day, what are the greatest guitar riffs of all time? There are lots of candidates, and it is difficult to select them in any particular order. I have a few candidates for the best ever, though. I would not pretend to rank them, but I think all of these songs have to be in the conversation for greatest guitar riff ever.

Even if you are not ranking your choices, it is difficult not to mention this song first: "Satisfaction," by the Rolling Stones:

OK, that's a pretty obvious choice. So is this one:

But enough of the Stones. We probably could go all night with them. Honky Tonk Women, anyone? Love that open G. Anyway, there are lots more candidates. Alice Cooper, for instance:

Turn that up. Really. You also have to consider Derek and the Dominos, which of course is just Eric Clapton, who was hoping George Harrison wouldn't realize Clapton was singing about banging Harrison's wife:

Yeah, George knew. Moving forward in the timeline, I think we have to give a nod to Mark Knopfler and Dire Straits. It's a live recording but, seriously, wait for it:

There are so many choices, I thought I should throw in at least a couple that you haven't thought of. Like Head East, "Never Been Any Reason:"

That's a no-shit great riff. So what else you going to put on the list? I thought about Deep Purple's "Smoke on the Water." I thought about "Highway to Hell" and "You Shook Me" by AC/DC. I thought about pretty much everything by Stevie Ray Vaughn. What would you put on the list?