I believe in the simplest form for calculating where lightning might strike, the tallest typically gets hit, typically regardless of the composition. (IF you're really interested, somewhere on the web is a 5th order differential equation you can use to predict where lightning will strike, enjoy. :)
The charge stored in a cloud seeks the line of least resistance to get to the ground. Most materials you're likely to find outdoor are better conductors than air. (You're competing against the resistance of air, and for practical purposes, as almost everything outdoors becomes a conductor at extreme voltages.) Even materials which may be insulators (like a PVC pipe sticking up on the top of a hill in a storm), but are wet, will still provide a lower path resistance than air. Also, just because you don't get hit with the main bolt, doesn't mean you are not a parallel path of slightly higher resistance, but you're still a path.
Further, at really high voltages and currents, electricity doesn't behave like it does in simple circuits, because the air, humidity, temperature, movement,charge, corona (not the beer) and a lot of other factors determine the actual path (that 5th order equation I don't care to revisit).
So the bottom line is, stay lower than other objects, and away from the tallest of objects. Lightning really does cause tree bark / limbs to explode off and kill or injure from the shrapnel.
2 years ago while camping, we were next to a group that set up a dining fly next to the tallest tree (yep, you guessed it). Lightning hit the tree, the kids standing next to the pole were zapped when the bolt jumped from the tree to the aluminum pole (they were also lower resistance paths to ground than air), and several others nearby were hit with flying bark. It was reeel clear where the bolt jumped to the pole. All survived, luckily. In this case, the lightning hit the highest object, ran down to a point 1 foot from the pole, and ran down the pole, while the corona reached out and zapped a couple of kids near by, and traveling on to the ground through the pole, tree and kids (and air).
I hope that makes sense.