Depends - which direction are you coming from into Hungary? Second the nod to the north side of Balaton - very nice now that the snow is gone and its getting warm. Check out the abbey at Pannonhalma just north of there. Easter is also good time to visit smaller villages. Holloko to the east of Budapest is Unesco world heritage site and lovely in Spring. Northeast of the country around Tokaj is also very interesting and special. Lost of wine cellars and great little villages. What kind of things do you like to do?