Lets see them.Although I don't usually browse the ornament shelves,I've never noticed too many mermaids....I once used a bunch of fist sized fake skulls to almost cover the bottom of an African cichlid tank.I read that some parts of the lakes are littered with real ones.
i think think it depends on the person and the type of fish you have. i personally like planted tanks with drift wood. i like more of a natural look. i have a 75g and a 10g that is planted and a 210g that has big pieces of drift wood and black sand. and what i mean by it depends on the fish you have is that dont put big cichlids a planted tank because they will uproot and move rocks from place to place. (personal experience)
Lately I just use driftwood pieces,fake or real.The plastic plants that I have always seem to get pulled up by the fish so I dont bother with them anymore.