AC/DC is the greatest live performance you can see. Angus is simply amazing to watch live. I have been a fan since 1977 when I seen them open for Cheap Trick and their songs do not all sound the same. I think you are believing that, because no one sounds like them, no one. Krokus was close, but didn't last. I guess when you are a fan of a group, you really don't think that ALL of their songs sound the same, although some are similar. Actually, there aren't many bands out there that their songs don't sound similar, um, maybe because its their sound?
Anyway, not to rant, but they sure did make a lot of money and garnered millions and millions of fans world wide, for playing those same 3 chords. Take a look at any of their live DVD's and wonder how 250,000 people could be wrong. 40+ years of Rock-N-Roll.
ZZ Top is another that plays 3 chords, and they sound pretty damn good too.