Older readers of the sf and fantasy genre as well as many gamers acknowlege the Robert E. Howard, J.R.R. Tolkien, H.P. Lovecraft, and Clark Ashton Smith influences on the two respective fields, but Fritz Leiber tends to be the forgotten man in this recollection effort.
I'm not going to go into a lot more detail here, as James Maliszewski has done a superb job of getting across the way I feel about Leiber and his writing and his influence on the fantasy field in his post today on the subject at his Grognardia site today.
In any event, Leiber's passing left us with gems of writing genius that will long outlive the author himself. And if I weren't in the middle of reading some of the stuff that's in my to-read queue at the moment, I would go back and honour Leiber today with a read of the earliest Fafhrd and the Gray Mouser stories. Oh, what the heck. :)