I find
Joe McNally's work with small flashguns inspirational
I was just about to say the exact same thing. I've been seeing Joe's photos for years without knowing (or caring at the time) who took them, but since taking up photography myself I can't get enough of seeing his work.
I've watched all of the videos he's done for KelbyTraining.com, bought both of his books and follow his blog religiously. Both an inspiration and education, an enclyclopedia of useful (and useless, but hilarious) knowledge.
I've just been waiting for him to tour back over this way and do a lighting workshop in the UK (or relatively close European country) so I can go check it out.
David Hobby (AKA "The Strobist") is another blog I follow, and seen some of his vids on Youtube working alone and with Joe McNally.
While not a fan of the man himself, I do find some of Chase Jarvis' work quite good. I like the experimental nature of some of his stuff (of course, he has pretty much endless supplies of cash to support it).
Other than that, there aren't any photographers that I find as an inspiration on the whole, more so individual images (by many different photographers) that I try to "reverse engineer" to figure out how it was done with regard to the lighting, and technical aspects, and then see if I can emulate similar or how I might be able to improve (subject to personal tastes
) upon it.