Planning to travel around Europe this August (2008) for a couple of weeks with a few mates. Plan is (at the moment):
Fly to Prague, then train to Berlin, Amsterdam and Paris.
Looking for one more city to fit roughly on that route - possibly Brussels so we can spend 3 nights at each place.
Anybody been to those cities before? recommend some places - nightlife, hostels, attractions etc
Prague is a great city you could spend a lot of time there, you can also do a day trip to Kutna Hora for not much to visit the famous osuary, a chapel decorated with human bones! Otherwise in town the obvious choices are the castle (hradceny) and the old town square with it's fancy clock that has a good view. Another great view can be found from the observatory in the large park on the hill south of the castle.
As for amsterdam I went in August a few years back and couldn't find anywhere to stay as it coincided with a massive festival - you may want to check for that and book ahead if it's on when you're there. I wouldn't worry too much though everything is open well into the morning. The Heineken museum may be worth a visit.
For places on route, Dresden (between Praha and Berlin), Cologne/Bonn/Dusseldorf (between Berlin and Amsterdam) and Bruxelles are all obvious stop offs. Antwerpen is another option in Belgium, whilst Brugge is probably the biggest attraction in Belgium and generally thought of much more highly than Bruxelles. You will have to change (in Antwerpen) on your way south from Amsterdam, but it is easy enough and there are lots of trains. From Brugge there is also one direct train a day to Paris, plus lots more changing in either Brixelles or Lille.
Another option if slightly more out of the way is Copenhagen, which has a direct Berlin-CPH train (which includes the train going on the ferry which is a bit different) and also a direct night train to Amsterdam.
Finally, you could extend your time in each city by a day, and then go for day trips. From Prague you could visit Kutna Hora or even Cesky Krumlov. You could leave Prague early and spend the day in Dresden en route to Berlin. You could go from Amsterdam to somewhere like Leiden, Delft, Harlem, Arnhem or Utrecht (or even more than one) and from any of Bruxelles, Gent, Brugge or Antwerp you could visit any or all of the others.
Also, note that if you are planning you trip in advance, you can save money by either flying or getting point to point tickets (booked in advance, specific train only) instead of using a pass (especially as many of the journeys you will be going on will require extra reservations or supplements anyway). You loose some flexibility, sure, but can save a load, and can then decide on day trips etc when you are there.
[ Edit: Edited on Feb 3, 2008, at 7:06 AM by Gelli ]