My favourite is a Hughes OH-6 Cayuse "Loach", my initial interest was fueled by a friend who is female Kiowa Pilot out of Fort Rucker and her insistence that I read "Low Level Hell" by Hugh Mills.

My favorite place on Fort Rucker is the Army Aviation Museum, where I have sat and admired Mr. Mills's Loach which is on display. The perfect spot to take a copy of Low Level Hell, read again, and imagine.

View The Collection: http://www.armyaviationmuseum.org/index.php/museum/aircraft-collection

My next would be the Bell OH-58D "Kiowa".

The CH-54A Tarhe scares me to death.