Just for anyone who needs anymore convincing about the holding-power of a Gorillapod, have some samples I just shot around the house. (sorry about quality, my good camera was the model for these shots)
Firstly, one of my typical macro-setups, 7D, 70-300L, all 68mm of kenko-tubes (and speedlite off to the side). Note the way i'm working with the ballhead-position, helps a lot with stability.
Second is a typical tree-branch shot with my EF-s 15-85, but instead I used my clothes-line pole, it's a lot more slippery than your average tree branch. 5' off the ground, I left it there for a full 5 minutes while I went inside to find my P&S without thinking twice if it would fall.
Third is a fence-shot, trick is to wind the two outermost legs as wide as possible from one direction, the middle leg comes from the other direction to hold it tight. This way it helps stop the wind blowing it over. I've taken panoramae with my samyang 35/1.4 in this exact position in the past.
Main thing to remember about a gorillapod is not expect or trust it too much (even a $1000 gitzo can blow over in enough wind), it just takes a little bit more getting used to than a normal tripod...