The Czech Republic has been a member of the European Union since 2004 and has a strong economy. As export to Europe is very important for the Czech Republic and domestic demand is growing rapidly, a .cz domain name may certainly not be lacking from your portfolio of European domain names. Once the Czech Republic switches to the Euro (which is expected on the long run), then this will make the link with Western Europe yet stronger.
In addition, a .cz registration has no special rules attached, the registration is very fast and Czech domain names are offered at an attractive price.