I have to admit that I have the Best of Eastern Europe 2007, but have not bought the 2008 book yet. I just reconfirmed a reservation I have in Prague, and arranged for a car. The hotel said I could pay in either Czech crowns OR Euro. So, I'm wondering if that's true for most of Prague? We're only going to be there 2 days then moving on to Austria and western Europe so it would be nice if we were able to get by on Euros.
Generally, the Euro charges will be higher than the Crowns charges. Not all the small merchants can or will accept Euros (bcuz they must convert them at cost to them or use them in private transactions). Euros are getting to be accepted everywhere, as many countries that currently do not use that currency will likely soon do so. Also, it is a strong and inflation-resistant money, unlike, say, US dollars!
I was in Prague last Sept. and did not remember seeing any euro payment options in restaurants, shows, concerts, entrance fees to tour sites, etc. This was true throughout my Eastern Europe trip.
We just returned from Prague and had to use Czech crowns for all of our transactions, as we ate at local spots that asked for their currency only. We just took out enough from the atm that we would need for our two days. However, you might be able to get by using a credit card and not have to even use their crowns!
Most places only accept Czech Koruna (Kc). Be aware there may be some mark up at the hotel if you use Euro. You are better off getting the maximum Kc amount out of a bank ATM for transactions. I would not use a credit card much in CZ either. Only large purchases at a known honest store such as Moser would I use a credit card and never let that card out of your sight! Otherwise the cashier/clerk can take an imprint and then you'll have to deal with fraud items. When paying always state out loud what Kc you are handing to them and double check the amount in change back is correct before moving away from the clerk. This also applies to any transaction inside of a bank. Do not ever change cash with a person on the street. These folks are dealing in funny money. You can always fill up your gas tank or buy picnic items at a gas station before leaving CZ to Austria with any left over Kc. Last time I drove it gas was cheaper in CZ than Austria. Its a long drive from Prague to Vienna.
They take both...some of the smaller merchant will give you KR change for Euros, so bring small Euro bills, just in case...