In addition to some of the other audio books already mentioned:
barry sadler: casca the eternal mercenary (the 22 books by the original author)
david weber and john ringo: empire of man - 4 books
jim butcher: dresden files - several books
neil gaiman: neverwhere
ben moor: undone - 3 series
william hodgson: house on the borderland
richard poe: brief history of the dead
james axler: deathlands - graphic audio production versions - 80+ books
pride and prejudice and zombies
mike resnick: starship series - 5 books
robert rankin: brightonomicon, knees up mother earth, the antipope, web site story
z.a. recht: morningstar strain(or plague of the dead) & thunder and ashes
jack mcdevitt: time travelers never die, the alex benedict series (not sure which ones are on audio book format)
elizabeth moon: the vatta war series