He had a good innings and did a lot of fantastic work. I would say a lot of his work is required reading even if (perhaps especially if) you don't agree with his Marxist analysis. Like C.B. Macpherson and E.P. Thompson, he is of those very important beasts: someone capable of provoking you and causing you to critically examine taken for granted assumptions about the shape of history. I would say that my belief in the value of "tradition" is a lot stronger for understanding the conditions under which traditions are invented, and I would say that my scepticism of revolution and the overturning of the established order is far better informed having read his The Age of Revolution. One of the true greats.