Before heading back home, we stopped at the little Siófoki to view lake Balaton. Siófoki has a nice old water tower for the views. And the best party beach is also in Siófoki, the Siófoki Nagystrand!
There's no beach per se, but a lakefront, and steps to get into the very nice water. The water runs shallow for a long time, so this a perfect place for a leisurely family swim.