RSV4 or Tuono V4R with an Austin racing can. Pure race bike sound. Added videos:
Second - Ducati L-twin (watercooled ones with wet clutches, not a fan of the bag of spanners sound of the early dukes with dry clutches when they're idling) with a full Termi system.
Third - Aprilia Rotax V-twin 1000cc.
You'd think the ducati and aprilia engine bikes would sound the exactly same, but but they don't, they have their own distinctive sound. The Aprilia has a much 'smoother' noise, whereas on the Ducati you can almost hear each cylinder firing. And in real life the Ducati sound has more bass and a bit more 'rasp', a more angy sound IMO - they can both wake the dead though, a sound you 'feel' more than you hear