My post of Cafe' Racer's reminded Greg of one of his favorite folk songs. I picked a different performance of the song than Greg suggested but, thanks to YouTube, you there are lots to choose from.
And since he brought it up, a little bit of the sound of a 1951 Vincent Black Lightning. I know that, in a previous comment, Doug mentioned the Aprilia as his favorite V twin sound. For me, some of these British twins give the best of the V twins a run for their money, at least for sound.