Mine is The Red Chief. I first read this story when I was about 12 years old - a long time ago now. I was captivated by the story, by the hero - Red Kangaroo (aka Cumbo Gunnerah) - and by the story-telling efforts of Ion idriess. I found it all very evocative. One of the images that remained in my mind was when the Red Chief invented his sharpened shield - and nearly killed his friend Giluram in a practice duel:
The top and bottom ends of Red Kangaroo's shield were smoothly rounded. But for some weeks past, as opportunity occurred, he, with stone axe, with stone rasp, water and sand had been carefully chipping and rubbing the rounded end to make it more wedge shaped, and gradually sharpening it, particularly the lower edge, very carefully, lest he damage the prized shield . . . But Giluram had leapt straight at him, and only by lightning-like footwork did Red Kangaroo dodge the club . . . "Now what about this!" and he smashed his shield straight at Red Kangaroo's face, while leaping in to swing his club low at his thigh. But at the very swing of the club he gave a startled grunt as his head was jerked back by Red Kangaroo's shield end, jarring heavily against his throat and jerking him to his knees. His mouth gasping in agonised alarm, he rolled to his chest and over, clawing for breath. A moment's silence, the Red Kangaroo was kneeling with Giluram's head on his knee. "Giluram, Giluram!" he cried. I didn't mean to do it - I didn't know I'd done it!" Much later, I read Drums of Mer, and liked that tale, too. It started me on collecting Idriess.
I also found Over The Range very interesting, as I used to live in the Kimberleys and met Weeda, then an old lady, who featured in that book. Likewise, Outlaws of the Leopolds, also situated in the Kimberleys, tells, amongst others, the story of Pigeon, aka Sandamara or Jandamarra, who led the Bunaba resistance. In Derby I knew old Banjo, who was the custodian of the Bunaba story of Jandamarra - and which gives a different slant on things!
Then, too, I like prospecting, and Idriess's books like Prospecting for Gold, Gold Dust and Ashes, and Men of the Jungle are interesting and informative, as is Lasseter's Last Ride. And of course Flynn of the Inland is, I think, so inspirational.