i've been listening to gary moore this evening and doing some thinking.
obviously his tone is always well tasty, one of the best. i checked out what gear he uses, and its 99% of the time some sort of random marshall with a booster. for the 'monsters of rock' album apparantly he took a stock jcm2000.
now i've been listening closely to his tone on this album, and i honestly think (ignoring for a moment his chops) if it wasn't for his vibrato and the really nice reverb/delay he would sound pretty bad - fizzy, somewhat undefined and almost solid stateish... take a listen to 'wishing well' and see if you agree.
obviously his vibrato really seperates him - i think he would sound great playing a through a valvestate practise amp.
but not just his vibrato, the reverb/delay is quite subtle, but very present, and it give the tone a real edge. i've always used reverb/delay to help the guitar sit better in a mix. maybe it would be interesting to use these effects as a device on their own.
just an anecdotal post, but i wonder if anyone else has opinons on this.