Although not forgotten, it should be noted what a great job Del Rey is doing with all of their Robert E. Howard re-issues in recent years. The most recent is The Horror Stories of Robert E. Howard,
Paizo's recently launched Planet Stories® imprint should be welcome too. From their Web site (bolded are some of the older writers):
Planet Stories® presents classic fantasy, science fiction, and science fantasy novels and short story collections to a generation of new readers and lifelong fans. Unforgettable tales from acknowledged masters like Michael Moorcock, Leigh Brackett, C.L. Moore, and Henry Kuttner stand side by side with lesser known but no less worthy yarns from tomorrow's superstars. Introductions from popular modern authors like Joe R. Lansdale, Ben Bova, and Michael Moorcock provide amusing and informative entry points to each book. With new releases every month, Planet Stories promises a master class in the genre aimed at building the greatest fantasy and science fiction library ever assembled.