Keszthely is the cultured old town at the western end of Lake Balaton, where the resort mood of the lakeshore meets aristocratic Hungary. It is less flashy than Siófok and less postcard-pretty than Tihany, but it has the strongest single sight on the lake: Festetics Palace, a grand Baroque residence with a library, park, and museum complex.
The town works well for travellers who want Balaton without surrendering entirely to beach life. You can swim at the municipal strand, walk the small centre, spend a half day at the palace, then take a bus or taxi to Lake Hévíz, one of Hungary's classic thermal bathing experiences.
Keszthely is also a good western anchor for the north shore. The wine villages, the beaches around Vonyarcvashegy, and the viewpoint at Balatongyörök are close enough for slow day trips by bike, car, or summer bus.