Re: What artists have been most influential to you and what gear did/do they use
For actual influence (ie..not just inspiration..) :
James Murphy...I think he used Ibanez's with EMG's into a JCM 800
I've only heard his playing on is one Testament album, but I dig it.
My personal influences:
James Hetfield: Vs and Explorers, Mesa Mark amps and EMGs, legendary sledgehammer
riffs.....the 80s albums are the backbone of thrash....
Jimmy Page: Lots of things, but I especially like his cutting tone with the Telecaster.
Jeff Hanneman: ESPs, EMGs and Marshall JCM800s, surgical precision panzer riffs and chromatic leads.
Prince: Lots of things, but I'm am mostly influenced by his rock playing on Purple Rain and Around The World in a Day (listen to the song TEMPTATION....

), especially when he used his Boss octave pedals. He used EMGs and Mesa Boogie.
John Petrucci: Superstrats and Mesa Mark amps.
Steve Vai: Ibanez guitars always and he used Marshall amps in my favorite years of his. Also very clever use of various delays, especially on Skyscraper, which is probably the best use of all-out shred on a popish rock album.
Yngwie J. Malmsteen: More of a tangential influence, but I love the warp speed alt-picked runs, sweeps, and wild vibrato, his perfect shred tone, and scalloped frets. Scalloped Strats through heavily boosted Marshalls.
Al Di Meola: Taylor acoustics, Les Pauls or PRS electrics and Mesa Boogie amps.