Mother and Father playing on the tennis courts, the rest of the family in the swimming pool, the Butler cracking open another bottle of Champagne, the sound of it tinkling playfully down the side of crystal as he pours it.... yeah right!
For me it is the sound of the birds and the insects in the garden, puntuated by tiny kids* playing in the back lane, riding their little trikes or bikes about with a rattle and a roar across dirt, loose stone and tarmac. The (older Primary school age) kids next door playing on their trampoline or waterslide. The sound (and smell) of grass being cut. The clicketty clack of a train at the station and traffic passing by the front gate. The occasional plane/helicopter flying over and someone's souped up nedmobile whining away on the A82 in the distance.
Surrounding all of this the sound of the Aspens in the front garden gently hissing in the breeze, performing their wispy serenade.
By night, all you hear is the distant, and somewhat reassuring low hum of the generators being tested at Aggreko, complete with the 'BEEP BEEP BEEP' of associated reversing lorries, and only Birdsong at dawn will interrupt this adequately.
* - For some reason they always seem to be of Pre School age. I doubt there is an infinite supply of them in the area, so I assume they will EVENTUALLY get older. Also, since the neighbours out the back got rid of their leylandii, I can actually see these kids for the first time ever, instead of just hearing them, and they all appear to be little girls.