I love Osaka. It's a great place, and the people are real "earthy" for lack of a better word. And I've always liked their dialect. A lot of comedians come from there, as it is the home of Yoshimoto Gekijo.
It's definitely worth a trip if you're ever in the area. I recommend you go to Dotombori and try some takoyaki by the Glico sign. If you know Japanese, go to Yoshimoto Gekijo to catch a show.
Kyoto and Kobe are nice, too. The whole Kansai area is a lot of fun.