The EU has $16 trillion yearly GDP. Wouldn't that make China #3?
(The Eurozone alone has ~$10 trillion yearly).
Don't come with the argument of, "oh they have all different governments and all different languages". State governments in the US hold a great fraction of legislative power (to the point where you're not a US lawyer, but a WA, TX or CL lawyer), and provinces in China have local languages (yes, languages - there's a point to using an ideographic writing system because you can use it for languages other than Mandarin) and not everyone speaks Mandarin.
EU, as of now, is far less unified than US. 11 of the 27 members have their own currencies. Some of the members are not part of the borderless Schengen Agreement. Sending stuff and money across EU is subject to international taxes and fees. People think of themself as German, French ... and not European.
> Sending stuff and money across EU is subject to international taxes and fees.
Generally no, from a consumer perspective. Perhaps I misunderstand what you refer to? There are some oddities, such as Switzerland not being in the EU which causes
The larger point is certainly correct: I would not consider EU a single economic entity at this point. It is progressing toward it, though, things such as the payment service/bank transfer unification are inevitably knitting the area together. As such it may be useful to include the union prospectively, if you will.
http://www.google.com/publicdata?ds=wb-wdi&met=ny_gdp_mk...