Hi ndn,
I think we all understand your frustration on this one - and we all went a little bit crazy when we first got here for the same reason. The problem is Switzerland is that up until recently there was only one company that merchants could use. As could be expected lack of competition meant that vendors got pulled over a barrel with respect to credit cards. In a country where change is embraced at a glacial pace, high processing fees didn't exactly encourage vendors to start offerring this facility to their customers.
We had a thread going about the difficulties faced by a vendor considering accepting credit cards, you may find it interesting for some background information:
http://www.englishforum.ch/help-tips...dit-cards.html
Another factor that hasn't exactly helped is that it is normal to charge fairly hefty yearly fees to the holder of a credit card. For this reason I refuse to have a Swiss credit card. Migros and Coop are now breaking with tradition and offerring credit cards without fees. Shock horror - the same thing the rest of us have enjoyed since ever I can remember, but the wheels turn extremely slowly in this country!
Also until recently credit cards had to be paid in full by the end of the month - effectively making them a charge card. I guess many Swiss therefore couldn't see the difference between getting a credit card (which they had to pay for), or paying with their EC/Maestro card.
These days the situation has improved significantly, credit cards are accepted by almost all major retailers with the exception of the supermarkets (but as other posters have said - this is changing). In the world of consumer electronics and computers it can still be a bit patchy. Generally if you look on toppreise.ch you'll see that the vendors who offer credit card facilities don't have the lowest prices. In the land of razor-thin margins they simply can't afford to offer it.
Mediamarkt however has no excuse - their margins are most definitely not razor thin (a quick comparison on toppreise.ch will show that!) and they are big enough to be able to negotiate a lower commission than anyone else. But they arrogantly refuse to entertain the idea. But with toppreise you can simply choose to support those business that do offer this facility
Just a side note - I recently had to aquire a whole lot of stuff from mediamarkt and I was carrying about 2.5k in my wallet - it was stolen and I was not happy. Don't fall into the trap of believing that there is no crime here. Usually people who have not yet been the victim of crime here tend to see the picture very differently to those who have - search the forum for other threads about crime.
On the positive side - there are plenty of cash machines in most locations so grabbing enough cash when you need it isn't a problem. Cash machines here won't charge you an additional fee on top of the normal charges levied by your bank - unlike ATMs in the US which slap on an additional $1.50-$2 in addition to your bank charges.