I first discovered Jack Vance's novels as a teenager, and his books enlivened a generally gloomy adolescence. Unlike just about any other writer I read at that age, I can read his work with equal pleasure today (more, in some cases, as life experience validates some of his insights).
He has clearly been huge influence on me (as well as many better writers, G.R.R. Martin to name but one), and if any visitors to this blog haven't yet read any Jack Vance, I'd suggest now is a good time to start.
It's a cliche, but we shouldn't mourn Jack Vance's death, but instead celebrate the magnificent body of work he produced, and be glad that his stories will still be around to enthral generations to come.