Berlin is an exciting city, and particularly great in the summer. I spent three days there on business last June. Unfortunately, I can't join you this summer - too booked already, and international airfares are sky high - but if you decide on a future one, post the dates some months in advance. It's well worth a trip from the States, imo.
For those looking for hotels, I was well content both with the treatment at the Hilton and the location. I was able to walk to a number of Berlin's wonderful museums, including my favorite, the one housing the Pergamom Temple. This is one of the world's great treasures, in my opinion, and not to be missed.