HI~~SAM~ You can go to Hannover ,I will go to Hannover. I believe in Hanover can learn Deutsch. Berlin is also quite good~~

You must go to Berlin, the most exciting town of Germany. :D The towns that apfelsaft recommended and others like München or Stuttgart a re nice but they really lack the dynamic energy and cultural diversity of Berlin. In Berlin, some poeple speak the local dialect, but actually only in Hannover people do not speak any distinct dialect.

If you want to learn german(Hochdeutsch), you should go to north germany,e.g. Koeln(Köln),Hannover,Hamburg etc. Because people there speak very good german, no dialect. But i think south germany has a good view.