Big Yellow Taxi was originally by Joni Mitchell, whose song Woodstock raises similar themes of worry about commercial culture.
I don't agree that places of power are a personal choice. Gaiman implies they are a real focus of natural energy. Later in the book he gives the example of the central point of the USA, the spot where a cardboard map of the 48 states would balance flat on its centre of gravity. (That Australian spelling looks out of context here!) The actual spot is implied to be a place of power, but the promoters shift it, and lose business - indicating that the trade for roadside attractions involves a subconscious knowledge about some telluric energy of the earth that we tap into. This discussion reminds me strongly of Carlos Castaneda's claim that Yacqui Indians could identify such spots using nothing more than spiritual sensitivity. Whether such channeling has any scientific basis is of course unknown. The explanation of places of power given by Wednesday is very similar to the explanation of the nagual Juan Matus, whose character could be a type for Odin.
Mr Nancy is the African Spider God Anansi, so his elephant is appropriate to Africa. Caernobog's centaur reminds me of the mongol horde. Odin and Fenrir the wolf of epic Ragnarok battle fame are discussed at http://en.wikipedia.org/wiki/Fenrir
. The wolf is central to Teutonic and Norse mythology. http://hafapea.com/norsepages/norse2.html
says Odin has two wolf companions, Freki and Geri, both translated 'Greedy'. The carousel itself is compared to a Tibetan Prayer Wheel.
Is it just me, or does Ragnarok make you think of Mars Attacks