Yeah, I liked Krakow a lot better than Warsaw. The central square there was one of my favorite people-watching places in all my eastern europe travels. Also ended up in an underground jazz club (I think it was in a former bomb shelter)... just googling, I think it was this place:
http://www.umuniaka.pl/index.html. Not sure if jazz is something you're into, but it was an awesome little venue.