Imaro
Legend
In the context of "modelling your PC", I think a trap choice would be (say) a feat called Toughness that doesn't, in actual play, have the mechanical result of making your PC tough.
Actually this is only considered a "trap" choice if you are playing a long-term campaign (in a one shot or short-term game it's not a bad feat to grab at all)... since it doesn't scale. However that seems to be more of a concern with optimization rather than, as @Dannyalcatraz pointed out, whether it makes your character tougher or not, because it does for all practical purposes do that.
Further I think how you and a few other posters are presenting the "trap" choices argument is a mis-characterization of how 3.x was actually designed. In Monte Cook's essay on the matter he isn't saying that there are blatant trap choices, what he was commenting on was the fact that certain options were designed with specific circumstances in mind, (again using toughness as an example it is more beneficial for a first level wizard to take since it almost doubles his hit points or to be used in one-shot/short campaign) but the 3.x books didn't offer the necessary guidance to people in order for them to understand when certain options as opposed to others would be beneficial.