Riders of the Purple Sage, War of the Worlds

Riders of the Purple Sage and War of the Worlds are each books that helped define a genre, Westerns and science fiction respectively.  But the former has dated very badly in the intervening century, while the latter is still one of the best books of its kind.

I don't know whether Riders was published as a pulp novel, but it certainly embodies the worst sins of the pulps -- cardboard characters, purple prose, racist (or anti-Mormon in the case).  I couldn't finish the novel, so maybe it has sterling qualities in the last 2/3, but it's hard for me to see why this novel is still read today.

War of the Worlds doesn't have memorable characters, either, although at less than half the length of Riders we don't feel the lack so much.  But the novel is memorable for its description of the quick descent in chaos, as the area surrounding London is ravaged by the Martians.  The novel is notable for its pitilessness.  Wells seems to say, "Just as humans had no mercy on the dodo, why should they expect any from others?"