In a previous article, mqd_117.3 said:
Has to be the Metro-Merlin!!!

Only because if you hear it departing, it means you're not on the "Torture
Tube".

My votes:
Spitfire
Lancaster bomber (because if one Merlin is good, 4 is better)
Vulcan bomber (loudest thing I've ever heard)


--
Paul Tomblin http://xcski.com/blogs/pt/
Quando omni flunkus moritati (when all else fails play dead)