The reality of Paris doesn't match up with the romantic image of Paris that Americans hold.
Instead of trying to see the sights, you might be better served by picking two or three cities and enjoying them for what they are. If there are touristy things there, great, but pick the cities for the general atmosphere.
Let's take the US. Without naming any specific sites you already know that LA is a warm, polluted metropolitan beach city with a bent towards show-biz and a large hispanic and Pacific rim community. And you know that Boston is an historic yankee city with a bent towards fisheries and a large Polish and Portuguese community (among others). Warm or cold, history or beach fun? You already know the answer because you are familiar with it.
My favorite spots in Northern continental Europe are Amsterdamm, Hameln, and Munchen. Tour from the Netherlands through mid-Northern Germany and down to Southern Germany. Laid-back towns with cafes and biergartens, so you can relax and take in the area and the people. Sure, there are touristy things to do (Rembrandt museum in Amsterdamm, etc) but you're not running from spot to spot.
Berlin was cool (and weird) to see when the wall was still up, but not sure how it is these days. I would now probably avoid Berlin and Frankfort.
Bern, Switzerland is a beautiful little city, but not much to see or do. Once again, just relax and take it all in. It is, however, a jumping-off point to head into the Bernese Oberland section of the Alps, with Interlaken probably being one of the most beautiful places in the world.
If you speak Spanish, Madrid is one big party. But beware that Spain and the areas of France and Italy that lie on the Mediterranean coast are not too English-friendly.
Buy some Frommers travel guides and see what feels right for you. They are quite descriptive and will probably help you decide what you want out of your trip.
Have fun!