If you want luxury in Europe, check into the nearest Holiday Inn. The biggest hotel room I've stayed in in all of Europe is the Holiday Inn in Frankfurt. I stayed there on a business trip. It was 25 floors and all rooms had a wrap around balcony. Not to mention at the breakfast you could actually get things like Frosted Flakes. Even the coffee tasted American according to a guy a work with. And the shower came complete with a tub which is not to be taken for granted in Europe!
Granted, normal people not traveling on business may not be able to afford a Holiday Inn. In Europe, they are very expensive. In Frankfurt, the Holiday Inn cost $275 a night with breakfast. Crazy. All for American comfort. So revel in them while you can in the states. Here in Europe, if you're like me, you'll stay at the local Ibis, a cheaper chain, when traveling on your own.
When my husband traveled on business he stayed in the Holiday Inn in Warsaw. They are the place to be in Europe on an expense account!