It's really an impossible question, but answering based on my purely personal preference (oh, nice alliteration, eh?) I have to answer Eric Clapton. Without EC, I guess GM wouldn't have been the same (like tons of other players of his generation, he loved Clapton and the Beano album in particular), but after having been inspired he took blues based guitar playing to a new level. GM's technical ability is way ahead of his idols (guys like Peter Green and Eric), but I'm still inclined to go for the "originals". Don't get me wrong, I have immense respect for Gary Moore, not least because he was a great proponent of the blues. But when the song in question is a Cream tune, I don't think Clapton can ever be topped by anyone.
About Clapton in general: I think a lot of people don't realize just how revolutionary his playing really was when he recorded with the Bluesbreakers. No one had sounded just like him before. The closest example I can think of really is Freddie King, but the sheer power of Clapton's playing was really unheard of. I my view he not only took the blues to a new level, but he also created the basis for all modern rock guitar with that one record. In many ways Clapton IS in fact God.