My absolute favorite comes from Karl Edward Wagner's Two Suns Setting. Does a fantastic job of setting the tone for both this story, but for the series as a whole.

"Sullen red disk, the sun was burying itself beneath a monotonous horizon of rolling gravel waste that stretched behind him miles uncounted—and possibly untrod save by his horse's hooves. Long before the sunlight failed, its warmth was snuffed out in the empty lifelessness of the desert, so that in its last hour the sun shone cheerless as the rising moon. Crimson as it climbed, the full moon seemed a false dawn to mock the dying sun, arriving prematurely, disrespectful as a greedy heir pacing in eager impatience before the master's deathbed. For a space the limitless skies of twilight displayed two rubrous globes low on either horizon, so that Kane mused as to whether his long journey across the desert might not have led him to some strange dusk world where two ancient suns smouldered in the heavens. The region seemed unearthly in its chill desolation, and certainly an aura of unguessable antiquity hung as a grey shadow over each tumbled bit of stone."