Hardware pricing SI vs. DE vs. UK

Every time I need to buy a new piece of hardware, I do some research to see where I can get the best price. Lately I've been finding out that virtually everything is cheaper abroad, even with the added cost of postage! What the heck? Something is obviously rotten in the state of Denmark or should I say Slovenia. Here are some of the items I bought (or consider buying) recently:

As you can see, the difference is not to be ignored. What I don't understand is where it comes from? All three (UK, DE and SI) are members of the EU so you obviously can't blame it on import taxes. If you ask me, it's either greed or something completely different. If you know the answer, leave a comment :) Cheers!

Prices were taken from the following websites and do not include shipping costs:
http://www.itx-warehouse.co.uk/
http://www.hpm-computer.de/
http://www.voelkner.de/
http://www.agt.si/
http://www.sestavi.si/
http://www.dinokomp.si/
http://www.hte.si/