Personally ACDC never inspired me much at all, some of my friends think it's the best thing eva and that's cool for them (we're all australian so maybe that's why) but they've got good solid songs and the guitar work is solid. But then again solidarity isn't what inspires me. Is it too cheap to add somebody like James Hetfield/Kirk Hammett to this debate? Although their guitar playing is pretty commercial some of their earlier compositions like on Master of Puppets or Ride the Lightening were breathtaking in my opinion.

I guess you have to define what you mean by best ... best as in fastest (satch?), most original(hendrix), most accurate(?), or most influencial(hendrix?)?