I have been a fan of Jim Lee since I picked up (Adjectiveless) X-Men #1 waaaaaay back in 93 or so and it sparked my love affair with comics.
Over the years, I have grown a discerning eye for comic books, and typically I pay attention to writing first - from Claremont to Bendis and Brubaker, I usually look at the writer. Johns, Jurgens and Morrison also top my favorites lists. But when it comes to art, Jim Lee is THE Man (Sorry, Stan).
He is the one artist that will make me pick up a book no matter who is writing it. I just finished Justice League #1 and have been rightfully reminded of why I absolutely love this guy's abilities!